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Sample records for finger thermoregulatory model

  1. Thermoregulatory control of finger blood flow

    NASA Technical Reports Server (NTRS)

    Wenger, C. B.; Roberts, M. F.; Nadel, E. R.; Stolwijk, J. A. J.

    1975-01-01

    In the present experiment, exercise was used to vary internal temperature and ambient air heat control was used to vary skin temperature. Finger temperature was fixed at about 35.7 C. Esophageal temperature was measured with a thermocouple at the level of the left atrium, and mean skin temperature was calculated from a weighted mean of thermocouple temperatures at different skin sites. Finger blood flow was measured by electrocapacitance plethysmography. An equation in these quantities is given which accounts for the data garnered.

  2. Thermoregulatory control of finger blood flow

    NASA Technical Reports Server (NTRS)

    Wenger, C. B.; Roberts, M. F.; Nadel, E. R.; Stolwijk, J. A. J.

    1975-01-01

    In the present experiment, exercise was used to vary internal temperature and ambient air heat control was used to vary skin temperature. Finger temperature was fixed at about 35.7 C. Esophageal temperature was measured with a thermocouple at the level of the left atrium, and mean skin temperature was calculated from a weighted mean of thermocouple temperatures at different skin sites. Finger blood flow was measured by electrocapacitance plethysmography. An equation in these quantities is given which accounts for the data garnered.

  3. Thermoregulatory modeling for cold stress.

    PubMed

    Xu, Xiaojiang; Tikuisis, Peter

    2014-07-01

    Modeling for cold stress has generated a rich history of innovation, has exerted a catalytic influence on cold physiology research, and continues to impact human activity in cold environments. This overview begins with a brief summation of cold thermoregulatory model development followed by key principles that will continue to guide current and future model development. Different representations of the human body are discussed relative to the level of detail and prediction accuracy required. In addition to predictions of shivering and vasomotor responses to cold exposure, algorithms are presented for thermoregulatory mechanisms. Various avenues of heat exchange between the human body and a cold environment are reviewed. Applications of cold thermoregulatory modeling range from investigative interpretation of physiological observations to forecasting skin freezing times and hypothermia survival times. While these advances have been remarkable, the future of cold stress modeling is still faced with significant challenges that are summarized at the end of this overview.

  4. Transient thermoregulatory model with graphics output

    NASA Technical Reports Server (NTRS)

    Grounds, D. J.

    1974-01-01

    A user's guide is presented for the transient version of the thermoregulatory model. The model is designed to simulate the transient response of the human thermoregulatory system to thermal inputs. The model consists of 41 compartments over which the terms of the heat balance are computed. The control mechanisms which are identified are sweating, vaso-constriction and vasodilation.

  5. Thermoregulatory modeling use and application in the military workforce.

    PubMed

    Yokota, Miyo; Berglund, Larry G; Xu, Xiaojiang

    2014-05-01

    Thermoregulatory models have been used in the military to quantify probabilities of individuals' thermal-related illness/injury. The uses of the models have diversified over the past decade. This paper revisits an overall view of selected thermoregulatory models used in the U.S. military and provides examples of actual practical military applications: 1) the latest military vehicle designed with armor and blast/bulletproof windows was assessed to predict crews' thermal strains levels inside vehicles under hot environment (air temperature [Ta]: 29-43 °C, dew point: 13 °C); 2) a military working dog (MWD) model was developed by modifying existing human thermoregulatory models with canine physical appearance and physiological mechanisms; 3) thermal tolerance range of individuals from a large military group (n = 100) exposed to 35 °C/40% relative humidity were examined using thermoregulatory modeling and multivariate statistical analyses. Model simulation results assist in the decisions for the strategic planning and preventions of heat stress.

  6. Thermoregulatory model for prediction of long-term cold exposure.

    PubMed

    Xu, Xiaojiang; Tikuisis, Peter; Gonzalez, Richard; Giesbrecht, Gordon

    2005-05-01

    A multi-segmental mathematical model has been developed for predicting shivering and thermoregulatory responses during long-term cold exposure. The present model incorporates new knowledge on shivering thermogenesis, including the control and maximal limits of its intensity, inhibition due to a low core temperature, and prediction of endurance time. The model also takes into account individual characteristics of age, height, weight, % body fat, and maximum aerobic capacity. The model was validated against three different cold conditions i.e. water immersion up to 38 h and air exposure. The predictions were found to be in good agreement with the observations.

  7. Thermoregulatory models of space shuttle and space station activities.

    PubMed

    Pisacane, Vincent L; Kuznetz, Lawrence H; Logan, James S; Clark, Johnathan B; Wissler, Eugene H

    2007-04-01

    Thermoregulation is critical for survival in space, especially during contingencies demanding of human cognitive and physical performance. A review of the negative feedback human thermoregulatory system is provided. The Advanced Crew Escape Suit is worn by astronauts during ascent and descent on the Space Shuttle to provide active cooling for nominal and contingency operations and protection from loss of cabin pressure mishaps. Failure of a thermal system control element during a recent Shuttle flight resulted in a single point failure that could have elevated cabin temperature, possibly resulting in cognitive deficits of the pilot during the reentry and landing phases. The efficacy of the existing cooling equipment and procedures for maintaining crew thermal comfort in the event of such a failure was assessed. The Wissler and 41-node thermoregulatory models were used to conduct a parametric study of Shuttle cabin temperatures and resulting thermal effects on crew. Under high metabolic loads, crewmember core temperatures and heat storage are shown to increase beyond allowable limits using this analysis. Resulting levels of thermal stress may exceed standardized limits, after which cognitive performance and manual tracking ability are diminished. The operational procedure for entry and landing during this failure scenario may result in significant thermal compromise to crewmembers, including cognitive and manual performance deficits. Revision of the flight rule governing crew actions during compromise of cabin thermal control has been undertaken to minimize thermal stress on returning Shuttle crewmembers. Modifications to the crew thermal protection system for the Shuttle are suggested.

  8. Thermoregulatory models. Recent research, current applications and future development.

    PubMed

    Werner, J

    1989-01-01

    This review traces the efforts of different fields of thermoregulatory modeling. The aims of the three diverging branches can be characterized by (i) insight into functional physiological mechanisms and prediction of physiological phenomena, (ii) prediction of human performance for the protection of industrial workers or military personnel, and (iii) prediction of the impact of accidents, diseases, and clinical treatments. Common current and future efforts may be recognized which improve the physiological quality of the models for purposes either of physiological research itself or of promotion of the field of application, namely, (i) to approach the models to real geometry and anatomy of the human body, (ii) to simulate more adequately heat transport processes induced by the circulating blood, (iii) to implement more sophisticated regulatory concepts, (iv) to take into account interaction with other regulatory systems. "Environmental Ergonomics" should be an adequate forum for linking these diversified fields together.

  9. A Self-Organising Model of Thermoregulatory Huddling

    PubMed Central

    Glancy, Jonathan; Groß, Roderich; Stone, James V.; Wilson, Stuart P.

    2015-01-01

    Endotherms such as rats and mice huddle together to keep warm. The huddle is considered to be an example of a self-organising system, because complex properties of the collective group behaviour are thought to emerge spontaneously through simple interactions between individuals. Groups of rodent pups display two such emergent properties. First, huddling undergoes a ‘phase transition’, such that pups start to aggregate rapidly as the temperature of the environment falls below a critical temperature. Second, the huddle maintains a constant ‘pup flow’, where cooler pups at the periphery continually displace warmer pups at the centre. We set out to test whether these complex group behaviours can emerge spontaneously from local interactions between individuals. We designed a model using a minimal set of assumptions about how individual pups interact, by simply turning towards heat sources, and show in computer simulations that the model reproduces the first emergent property—the phase transition. However, this minimal model tends to produce an unnatural behaviour where several smaller aggregates emerge rather than one large huddle. We found that an extension of the minimal model to include heat exchange between pups allows the group to maintain one large huddle but eradicates the phase transition, whereas inclusion of an additional homeostatic term recovers the phase transition for large huddles. As an unanticipated consequence, the extended model also naturally gave rise to the second observed emergent property—a continuous pup flow. The model therefore serves as a minimal description of huddling as a self-organising system, and as an existence proof that group-level huddling dynamics emerge spontaneously through simple interactions between individuals. We derive a specific testable prediction: Increasing the capacity of the individual to generate or conserve heat will increase the range of ambient temperatures over which adaptive thermoregulatory huddling

  10. A Self-Organising Model of Thermoregulatory Huddling.

    PubMed

    Glancy, Jonathan; Groß, Roderich; Stone, James V; Wilson, Stuart P

    2015-09-01

    Endotherms such as rats and mice huddle together to keep warm. The huddle is considered to be an example of a self-organising system, because complex properties of the collective group behaviour are thought to emerge spontaneously through simple interactions between individuals. Groups of rodent pups display two such emergent properties. First, huddling undergoes a 'phase transition', such that pups start to aggregate rapidly as the temperature of the environment falls below a critical temperature. Second, the huddle maintains a constant 'pup flow', where cooler pups at the periphery continually displace warmer pups at the centre. We set out to test whether these complex group behaviours can emerge spontaneously from local interactions between individuals. We designed a model using a minimal set of assumptions about how individual pups interact, by simply turning towards heat sources, and show in computer simulations that the model reproduces the first emergent property--the phase transition. However, this minimal model tends to produce an unnatural behaviour where several smaller aggregates emerge rather than one large huddle. We found that an extension of the minimal model to include heat exchange between pups allows the group to maintain one large huddle but eradicates the phase transition, whereas inclusion of an additional homeostatic term recovers the phase transition for large huddles. As an unanticipated consequence, the extended model also naturally gave rise to the second observed emergent property--a continuous pup flow. The model therefore serves as a minimal description of huddling as a self-organising system, and as an existence proof that group-level huddling dynamics emerge spontaneously through simple interactions between individuals. We derive a specific testable prediction: Increasing the capacity of the individual to generate or conserve heat will increase the range of ambient temperatures over which adaptive thermoregulatory huddling will

  11. Testing the Fitness Consequences of the Thermoregulatory and Parental Care Models for the Origin of Endothermy

    PubMed Central

    Clavijo-Baque, Sabrina; Bozinovic, Francisco

    2012-01-01

    The origin of endothermy is a puzzling phenomenon in the evolution of vertebrates. To address this issue several explicative models have been proposed. The main models proposed for the origin of endothermy are the aerobic capacity, the thermoregulatory and the parental care models. Our main proposal is that to compare the alternative models, a critical aspect is to determine how strongly natural selection was influenced by body temperature, and basal and maximum metabolic rates during the evolution of endothermy. We evaluate these relationships in the context of three main hypotheses aimed at explaining the evolution of endothermy, namely the parental care hypothesis and two hypotheses related to the thermoregulatory model (thermogenic capacity and higher body temperature models). We used data on basal and maximum metabolic rates and body temperature from 17 rodent populations, and used intrinsic population growth rate (Rmax) as a global proxy of fitness. We found greater support for the thermogenic capacity model of the thermoregulatory model. In other words, greater thermogenic capacity is associated with increased fitness in rodent populations. To our knowledge, this is the first test of the fitness consequences of the thermoregulatory and parental care models for the origin of endothermy. PMID:22606328

  12. User's instructions for the 41-node thermoregulatory model (steady state version)

    NASA Technical Reports Server (NTRS)

    Leonard, J. I.

    1974-01-01

    A user's guide for the steady-state thermoregulatory model is presented. The model was modified to provide conversational interaction on a remote terminal, greater flexibility for parameter estimation, increased efficiency of convergence, greater choice of output variable and more realistic equations for respiratory and skin diffusion water losses.

  13. Mechanical model of a single tendon finger

    NASA Astrophysics Data System (ADS)

    Rossi, Cesare; Savino, Sergio

    2013-10-01

    The mechanical model of a single tendon three phalanxes finger is presented. By means of the model both kinematic and dynamical behavior of the finger itself can be studied. This finger is a part of a more complex mechanical system that consists in a four finger grasping device for robots or in a five finger human hand prosthesis. A first prototype has been realized in our department in order to verify the real behavior of the model. Some results of both kinematic and dynamical behavior are presented.

  14. Fingering in Stochastic Growth Models

    PubMed Central

    Aristotelous, Andreas C.; Durrett, Richard

    2015-01-01

    Motivated by the widespread use of hybrid-discrete cellular automata in modeling cancer, two simple growth models are studied on the two dimensional lattice that incorporate a nutrient, assumed to be oxygen. In the first model the oxygen concentration u(x, t) is computed based on the geometry of the growing blob, while in the second one u(x, t) satisfies a reaction-diffusion equation. A threshold θ value exists such that cells give birth at rate β(u(x, t) − θ)+ and die at rate δ(θ − u(x, t)+. In the first model, a phase transition was found between growth as a solid blob and “fingering” at a threshold θc = 0.5, while in the second case fingering always occurs, i.e., θc = 0. PMID:26430353

  15. Integrating a human thermoregulatory model with a clothing model to predict core and skin temperatures.

    PubMed

    Yang, Jie; Weng, Wenguo; Wang, Faming; Song, Guowen

    2017-05-01

    This paper aims to integrate a human thermoregulatory model with a clothing model to predict core and skin temperatures. The human thermoregulatory model, consisting of an active system and a passive system, was used to determine the thermoregulation and heat exchanges within the body. The clothing model simulated heat and moisture transfer from the human skin to the environment through the microenvironment and fabric. In this clothing model, the air gap between skin and clothing, as well as clothing properties such as thickness, thermal conductivity, density, porosity, and tortuosity were taken into consideration. The simulated core and mean skin temperatures were compared to the published experimental results of subject tests at three levels of ambient temperatures of 20 °C, 30 °C, and 40 °C. Although lower signal-to-noise-ratio was observed, the developed model demonstrated positive performance at predicting core temperatures with a maximum difference between the simulations and measurements of no more than 0.43 °C. Generally, the current model predicted the mean skin temperatures with reasonable accuracy. It could be applied to predict human physiological responses and assess thermal comfort and heat stress.

  16. Finite-difference electromagnetic deposition/thermoregulatory model: comparison between theory and measurements

    SciTech Connect

    Spiegel, R.J.; Fatmi, M.B.; Ward, T.R.

    1987-01-01

    The rate of the electromagnetic energy deposition and the resultant thermoregulatory response of a block model of a squirrel monkey exposed to plane-wave fields at 350 MHz were calculated using a finite-difference procedure. Noninvasive temperature measurements in live squirrel monkeys under similar exposure conditions were obtained using Vitek probes. Calculations exhibit reasonable correlation with the measured data, especially for the rise in colonic temperature.

  17. Measured body composition and geometrical data of four "virtual family" members for thermoregulatory modeling

    NASA Astrophysics Data System (ADS)

    Xu, Xiaojiang; Rioux, Timothy P.; MacLeod, Tynan; Patel, Tejash; Rome, Maxwell N.; Potter, Adam W.

    2016-08-01

    The purpose of this paper is to develop a database of tissue composition, distribution, volume, surface area, and skin thickness from anatomically correct human models, the virtual family. These models were based on high-resolution magnetic resonance imaging (MRI) of human volunteers, including two adults (male and female) and two children (boy and girl). In the segmented image dataset, each voxel is associated with a label which refers to a tissue type that occupies up that specific cubic millimeter of the body. The tissue volume was calculated from the number of the voxels with the same label. Volumes of 24 organs in body and volumes of 7 tissues in 10 specific body regions were calculated. Surface area was calculated from the collection of voxels that are touching the exterior air. Skin thicknesses were estimated from its volume and surface area. The differences between the calculated and original masses were about 3 % or less for tissues or organs that are important to thermoregulatory modeling, e.g., muscle, skin, and fat. This accurate database of body tissue distributions and geometry is essential for the development of human thermoregulatory models. Data derived from medical imaging provide new effective tools to enhance thermal physiology research and gain deeper insight into the mechanisms of how the human body maintains heat balance.

  18. Measured body composition and geometrical data of four "virtual family" members for thermoregulatory modeling.

    PubMed

    Xu, Xiaojiang; Rioux, Timothy P; MacLeod, Tynan; Patel, Tejash; Rome, Maxwell N; Potter, Adam W

    2017-03-01

    The purpose of this paper is to develop a database of tissue composition, distribution, volume, surface area, and skin thickness from anatomically correct human models, the virtual family. These models were based on high-resolution magnetic resonance imaging (MRI) of human volunteers, including two adults (male and female) and two children (boy and girl). In the segmented image dataset, each voxel is associated with a label which refers to a tissue type that occupies up that specific cubic millimeter of the body. The tissue volume was calculated from the number of the voxels with the same label. Volumes of 24 organs in body and volumes of 7 tissues in 10 specific body regions were calculated. Surface area was calculated from the collection of voxels that are touching the exterior air. Skin thicknesses were estimated from its volume and surface area. The differences between the calculated and original masses were about 3 % or less for tissues or organs that are important to thermoregulatory modeling, e.g., muscle, skin, and fat. This accurate database of body tissue distributions and geometry is essential for the development of human thermoregulatory models. Data derived from medical imaging provide new effective tools to enhance thermal physiology research and gain deeper insight into the mechanisms of how the human body maintains heat balance.

  19. Measured body composition and geometrical data of four ``virtual family'' members for thermoregulatory modeling

    NASA Astrophysics Data System (ADS)

    Xu, Xiaojiang; Rioux, Timothy P.; MacLeod, Tynan; Patel, Tejash; Rome, Maxwell N.; Potter, Adam W.

    2017-03-01

    The purpose of this paper is to develop a database of tissue composition, distribution, volume, surface area, and skin thickness from anatomically correct human models, the virtual family. These models were based on high-resolution magnetic resonance imaging (MRI) of human volunteers, including two adults (male and female) and two children (boy and girl). In the segmented image dataset, each voxel is associated with a label which refers to a tissue type that occupies up that specific cubic millimeter of the body. The tissue volume was calculated from the number of the voxels with the same label. Volumes of 24 organs in body and volumes of 7 tissues in 10 specific body regions were calculated. Surface area was calculated from the collection of voxels that are touching the exterior air. Skin thicknesses were estimated from its volume and surface area. The differences between the calculated and original masses were about 3 % or less for tissues or organs that are important to thermoregulatory modeling, e.g., muscle, skin, and fat. This accurate database of body tissue distributions and geometry is essential for the development of human thermoregulatory models. Data derived from medical imaging provide new effective tools to enhance thermal physiology research and gain deeper insight into the mechanisms of how the human body maintains heat balance.

  20. Exercise activates compensatory thermoregulatory reaction in rats: a modeling study

    PubMed Central

    Yoo, Yeonjoo; LaPradd, Michelle; Kline, Hannah; Zaretskaia, Maria V.; Behrouzvaziri, Abolhassan; Rusyniak, Daniel E.; Molkov, Yaroslav I.

    2015-01-01

    The importance of exercise is increasingly emphasized for maintaining health. However, exercise itself can pose threats to health such as the development of exertional heat shock in warm environments. Therefore, it is important to understand how the thermoregulation system adjusts during exercise and how alterations of this can contribute to heat stroke. To explore this we measured the core body temperature of rats (Tc) running for 15 min on a treadmill at various speeds in two ambient temperatures (Ta = 25°C and 32°C). We assimilated the experimental data into a mathematical model that describes temperature changes in two compartments of the body, representing the muscles and the core. In our model the core body generates heat to maintain normal body temperature, and dissipates it into the environment. The muscles produce additional heat during exercise. According to the estimation of model parameters, at Ta = 25°C, the heat generation in the core was progressively reduced with the increase of the treadmill speed to compensate for a progressive increase in heat production by the muscles. This compensation was ineffective at Ta = 32°C, which resulted in an increased rate of heat accumulation with increasing speed, as opposed to the Ta = 25°C case. Interestingly, placing an animal on a treadmill increased heat production in the muscles even when the treadmill speed was zero. Quantitatively, this “ready-to-run” phenomenon accounted for over half of the heat generation in the muscles observed at maximal treadmill speed. We speculate that this anticipatory response utilizes stress-related circuitry. PMID:26472864

  1. An improved thermoregulatory model for cooling garment applications with transient metabolic rates

    NASA Astrophysics Data System (ADS)

    Westin, Johan K.

    Current state-of-the-art thermoregulatory models do not predict body temperatures with the accuracies that are required for the development of automatic cooling control in liquid cooling garment (LCG) systems. Automatic cooling control would be beneficial in a variety of space, aviation, military, and industrial environments for optimizing cooling efficiency, for making LCGs as portable and practical as possible, for alleviating the individual from manual cooling control, and for improving thermal comfort and cognitive performance. In this study, we adopt the Fiala thermoregulatory model, which has previously demonstrated state-of-the-art predictive abilities in air environments, for use in LCG environments. We validate the numerical formulation with analytical solutions to the bioheat equation, and find our model to be accurate and stable with a variety of different grid configurations. We then compare the thermoregulatory model's tissue temperature predictions with experimental data where individuals, equipped with an LCG, exercise according to a 700 W rectangular type activity schedule. The root mean square (RMS) deviation between the model response and the mean experimental group response is 0.16°C for the rectal temperature and 0.70°C for the mean skin temperature, which is within state-of-the-art variations. However, with a mean absolute body heat storage error 3¯ BHS of 9.7 W˙h, the model fails to satisfy the +/-6.5 W˙h accuracy that is required for the automatic LCG cooling control development. In order to improve model predictions, we modify the blood flow dynamics of the thermoregulatory model. Instead of using step responses to changing requirements, we introduce exponential responses to the muscle blood flow and the vasoconstriction command. We find that such modifications have an insignificant effect on temperature predictions. However, a new vasoconstriction dependency, i.e. the rate of change of hypothalamus temperature weighted by the

  2. Scrotal thermoregulatory model and assessment of the impairment of scrotal temperature control in varicocele.

    PubMed

    Mariotti, Alessandro; Di Carlo, Luigi; Orlando, Giuseppe; Corradini, Maria Letizia; Di Donato, Luigi; Pompa, Paolo; Iezzi, Roberto; Cotroneo, Antonio Raffaele; Romani, Gian Luca; Merla, Arcangelo

    2011-02-01

    Varicocele is defined as the pathological dilatation of the pampiniform plexus and scrotal veins with venous blood reflux. Varicocele may impair scrotal thermoregulation and spermatogenesis, even when present in asymptomatic forms. In this study, we use the control system theory to model scrotal thermoregulation in response to a standardized cold challenge in order to study the functional thermal impairment secondary to varicocele. The proposed model is based on a homeostatic negative feedback loop, characterized by four distinct parameters, which describe how the control mechanisms are activated and maintained. Thermal infrared images series from 49 young patients suffering from left varicocele and 17 healthy controls were processed. With respect to healthy controls, left varicocele patients presented higher basal scrotal temperature and faster recovery of the left hemiscrotum. The model indicated that varicocele alters local heat exchange processes among cutaneous layers and inner structures. The estimated model parameters help in the assessment of the scrotal thermoregulatory impairment secondary to the disease.

  3. Use of Thermoregulatory Models to Enhance Space Shuttle and Space Station operations and Review of Human Thermoregulatory Control

    NASA Technical Reports Server (NTRS)

    Pisacane, V. L.; Kuznetz, L. H.; Logan, J. S.; Clark, J. B.; Wissler, E. H.

    2007-01-01

    Thermoregulation in the space environment is critical for survival, especially in off- nominal operations. In such cases, mathematical models of thermoregulation are frequently employed to evaluate safety-of-flight issues in various human mission scenarious. In this study, the 225-node Wissler model and the 41-Node Metabolic Man model are employed to evaluate the effects of such a scenario. Metabolic loads on astronauts wearing the advanced crew escape suit (ACES) and liquid cooled ventilation garment (LCVG) are imposed on astronauts exposed to elevated cabin temperatures resulting from a systems failure. The study indicates that the performance of the ACES/LCVG cooling system is marginal. Increases in workload and or cabin temperature above nominal will increase rectal temperature, stored heat load, heart rate, and sweating, which could lead to deficits in the performance of cognitive and motor tasks. This is of concern as the ACES/LCVG is employed during Shuttle decent when the likelihood of a safe landing may be compromised. The study indicates that the most effective mitigation strategy would be to decrease the LCVG inlet temperature.

  4. Self-organised criticality in the evolution of a thermodynamic model of rodent thermoregulatory huddling

    PubMed Central

    2017-01-01

    A thermodynamic model of thermoregulatory huddling interactions between endotherms is developed. The model is presented as a Monte Carlo algorithm in which animals are iteratively exchanged between groups, with a probability of exchanging groups defined in terms of the temperature of the environment and the body temperatures of the animals. The temperature-dependent exchange of animals between groups is shown to reproduce a second-order critical phase transition, i.e., a smooth switch to huddling when the environment gets colder, as measured in recent experiments. A peak in the rate at which group sizes change, referred to as pup flow, is predicted at the critical temperature of the phase transition, consistent with a thermodynamic description of huddling, and with a description of the huddle as a self-organising system. The model was subjected to a simple evolutionary procedure, by iteratively substituting the physiologies of individuals that fail to balance the costs of thermoregulation (by huddling in groups) with the costs of thermogenesis (by contributing heat). The resulting tension between cooperative and competitive interactions was found to generate a phenomenon called self-organised criticality, as evidenced by the emergence of avalanches in fitness that propagate across many generations. The emergence of avalanches reveals how huddling can introduce correlations in fitness between individuals and thereby constrain evolutionary dynamics. Finally, a full agent-based model of huddling interactions is also shown to generate criticality when subjected to the same evolutionary pressures. The agent-based model is related to the Monte Carlo model in the way that a Vicsek model is related to an Ising model in statistical physics. Huddling therefore presents an opportunity to use thermodynamic theory to study an emergent adaptive animal behaviour. In more general terms, huddling is proposed as an ideal system for investigating the interaction between self

  5. Ethnic differences in thermoregulatory responses during resting, passive and active heating: application of Werner's adaptation model.

    PubMed

    Lee, Joo-Young; Wakabayashi, Hitoshi; Wijayanto, Titis; Hashiguchi, Nobuko; Saat, Mohamed; Tochihara, Yutaka

    2011-12-01

    For the coherent understanding of heat acclimatization in tropical natives, we compared ethnic differences between tropical and temperate natives during resting, passive and active heating conditions. Experimental protocols included: (1) a resting condition (an air temperature of 28°C with 50% RH), (2) a passive heating condition (28°C with 50% RH; leg immersion in a hot tub at a water temperature of 42°C), and (3) an active heating condition (32°C with 70% RH; a bicycle exercise). Morphologically and physically matched tropical natives (ten Malaysian males, MY) and temperate natives (ten Japanese males, JP) participated in all three trials. The results saw that: tropical natives had a higher resting rectal temperature and lower hand and foot temperatures at rest, smaller rise of rectal temperature and greater temperature rise in bodily extremities, and a lower sensation of thirst during passive and active heating than the matched temperate natives. It is suggested that tropical natives' homeostasis during heating is effectively controlled with the improved stability in internal body temperature and the increased capability of vascular circulation in extremities, with a lower thirst sensation. The enhanced stability of internal body temperature and the extended thermoregulatory capability of vascular circulation in the extremities of tropical natives can be interpreted as an interactive change to accomplish a thermal dynamic equilibrium in hot environments. These heat adaptive traits were explained by Wilder's law of initial value and Werner's process and controller adaptation model.

  6. Lumped versus distributed thermoregulatory control: results from a three-dimensional dynamic model.

    PubMed

    Werner, J; Buse, M; Foegen, A

    1989-01-01

    In this study we use a three-dimensional model of the human thermal system, the spatial grid of which is 0.5 ... 1.0 cm. The model is based on well-known physical heat-transfer equations, and all parameters of the passive system have definite physical values. According to the number of substantially different areas and organs, 54 spatially different values are attributed to each physical parameter. Compatibility of simulation and experiment was achieved solely on the basis of physical considerations and physiological basic data. The equations were solved using a modification of the alternating direction implicit method. On the basis of this complex description of the passive system close to reality, various lumped and distributed parameter control equations were tested for control of metabolic heat production, blood flow and sweat production. The simplest control equations delivering results on closed-loop control compatible with experimental evidence were determined. It was concluded that it is essential to take into account the spatial distribution of heat production, blood flow and sweat production, and that at least for control of shivering, distributed controller gains different from the pattern of distribution of muscle tissue are required. For sweat production this is not so obvious, so that for simulation of sweating control after homogeneous heat load a lumped parameter control may be justified. Based on these conclusions three-dimensional temperature profiles for cold and heat load and the dynamics for changes of the environmental conditions were computed. In view of the exact simulation of the passive system and the compatibility with experimentally attainable variables there is good evidence that those values extrapolated by the simulation are adequately determined. The model may be used both for further analysis of the real thermoregulatory mechanisms and for special applications in environmental and clinical health care.

  7. Thermoregulatory response thresholds during spinal anesthesia.

    PubMed

    Kurz, A; Sessler, D I; Schroeder, M; Kurz, M

    1993-10-01

    Reportedly, during spinal anesthesia, the shivering threshold is reduced approximately 1 degree C but the vasoconstriction threshold remains normal. Such divergence between the shivering and vasoconstriction thresholds is an unusual pattern of thermoregulatory impairment and suggests that the mechanisms of impairment during regional anesthesia may be especially complex. Accordingly, we sought to define the pattern of thermoregulatory impairment during spinal anesthesia by measuring response thresholds. Seven healthy women volunteered to participate on two study days. On one day, we evaluated thermoregulatory responses to hypothermia and hyperthermia during spinal anesthesia; on the other day, responses were evaluated without anesthesia. Upper body skin temperature was kept constant throughout the study. The volunteers were warmed via the lower body and cooled by central venous infusion of cold fluid. The core temperatures triggering a sweating rate of 40 g.m-2 x h-1, a finger flow of 0.1 mL/min, and a marked and sustained increase in oxygen consumption were considered the thermoregulatory thresholds for sweating, vasoconstriction, and shivering, respectively. Spinal anesthesia significantly decreased the thresholds for vasoconstriction and shivering, and the decrease in each was approximately 0.5 degree C. The range of temperatures not triggering thermoregulatory responses (those between sweating and vasoconstriction) was 0.9 +/- 0.6 degree C during spinal anesthesia. The synchronous decrease in the shivering and vasoconstriction thresholds during spinal anesthesia is consistent with thermoregulatory impairment resulting from altered afferent thermal input.

  8. Modelling and quantification of the thermoregulatory responses of the developing avian embryo: electrical analogies of a physiological system.

    PubMed

    Youssef, Ali; Exadaktylos, Vasileios; Berckmans, Daniel

    2014-08-01

    Homeothermic animals, including birds, try to keep their body temperature at a constant level within certain boundaries by using thermoregulatory mechanisms. However, during incubation, the thermoregulatory system of the chicken embryo evolves through different stages from a poikilothermic to a homeothermic system. Hence, the thermal response of the fertile egg to changes in ambient temperature is different from one day to another during the embryonic development. The incubated egg can be considered as a physical (thermal) system, which transfers energy (heat) down a potential gradient (temperature difference). The heat flow between the micro-environment and the eggshell under a thermal driving force (temperature difference) has been studied in the past by using the analogy to the flow of electric charge under an electromotive-force. In this work, the thermal-response of incubated eggs to a step-increase in ambient-air temperature is studied and modelled. It is shown that the incubated egg is reacting as a first-order system between embryonic days ED01 and ED13, while, starting from ED14, the egg is reacting as a second-order system. This extends the existing RC (resistor-capacitor) circuit analogue to an RLC (resistor-inductor-capacitor) circuit analogue at the later stage of incubation. The concept of considering the fertile egg and its surrounding environment as an energy-handling device is introduced in this paper. It is suggested that the thermoregulation of the embryo has a thermal induction-like effect starting from ED14 and increasing gradually till hatching.

  9. Crossover from capillary fingering to viscous fingering for immiscible unstable flow:Experiment and modeling

    NASA Astrophysics Data System (ADS)

    Ferer, M.; Ji, Chuang; Bromhal, Grant S.; Cook, Joshua; Ahmadi, Goodarz; Smith, Duane H.

    2004-07-01

    Invasion percolation with trapping (IPT) and diffusion-limited aggregation (DLA) are simple fractal models, which are known to describe two-phase flow in porous media at well defined, but unphysical limits of the fluid properties and flow conditions. A decade ago, Fernandez, Rangel, and Rivero predicted a crossover from IPT (capillary fingering) to DLA (viscous fingering) for the injection of a zero-viscosity fluid as the injection velocity was increased from zero. [J. F. Fernandez, R. Rangel, and J. Rivero, Phys. Rev. Lett. 67, 2958 (1991)]. We have performed experiments in which air is injected into a glass micromodel to displace water. These experiments clearly demonstrate this crossover as the injection velocity of the air is increased. Furthermore, simulations, using our standard pore-level model, also support the predicted IPT-to-DLA crossover, as well as the predicted power-law behavior of the characteristic crossover length.

  10. Patterns of Dupuytren disease in fingers: studying correlations with a multivariate ordinal logit model.

    PubMed

    Lanting, Rosanne; Nooraee, Nazanin; Werker, Paul M N; van den Heuvel, Edwin R

    2014-09-01

    Dupuytren disease affects fingers in a variable fashion. Knowledge about specific disease patterns (phenotype) based on location and severity of the disease is lacking. In this cross-sectional study, 344 primary affected hands with Dupuytren disease were physically examined. The Pearson correlation coefficient between the coexistence of Dupuytren disease in pairs of fingers was calculated, and agglomerative hierarchical clustering was applied to identify possible clusters of affected fingers. With a multivariate ordinal logit model, the authors studied the correlation on severity, taking into account age and sex, and tested hypotheses on independence between groups of fingers. The ring finger was most frequently affected by Dupuytren disease, and contractures were seen in 15.1 percent of affected rays. The severity of thumb and index finger, middle and ring fingers, and middle and little fingers was significantly correlated. Occurrences in pairs of fingers were highest in the middle and ring fingers and lowest in the thumb and index finger. Correlation between the ring and little fingers and a correlation between fingers from the ulnar and radial sides could not be demonstrated. Rays on the ulnar side of the hand are predominantly affected. The middle finger is substantially correlated with other fingers on the ulnar side, and the thumb and index finger are correlated; however, there was no evidence that the ulnar side and the radial side were correlated in any way, which suggests that occurrence on one side of the hand does not predict Dupuytren disease on the other side of the hand. Risk, III.

  11. Development of a mechanism-based pharmacokinetic/pharmacodynamic model to characterize the thermoregulatory effects of serotonergic drugs in mice.

    PubMed

    Jiang, Xi-Ling; Shen, Hong-Wu; Mager, Donald E; Schmidt, Stephan; Yu, Ai-Ming

    2016-09-01

    We have shown recently that concurrent harmaline, a monoamine oxidase-A inhibitor (MAOI), potentiates serotonin (5-HT) receptor agonist 5-methoxy-N,N-dimethyltryptamine (5-MeO-DMT)-induced hyperthermia. The objective of this study was to develop an integrated pharmacokinetic/pharmacodynamic (PK/PD) model to characterize and predict the thermoregulatory effects of such serotonergic drugs in mice. Physiological thermoregulation was described by a mechanism-based indirect-response model with adaptive feedback control. Harmaline-induced hypothermia and 5-MeO-DMT-elicited hyperthermia were attributable to the loss of heat through the activation of 5-HT1A receptor and thermogenesis via the stimulation of 5-HT2A receptor, respectively. Thus serotonergic 5-MeO-DMT-induced hyperthermia was readily distinguished from handling/injection stress-provoked hyperthermic effects. This PK/PD model was able to simultaneously describe all experimental data including the impact of drug-metabolizing enzyme status on 5-MeO-DMT and harmaline PK properties, and drug- and stress-induced simple hypo/hyperthermic and complex biphasic effects. Furthermore, the modeling results revealed a 4-fold decrease of apparent SC50 value (1.88-0.496 µmol/L) for 5-MeO-DMT when harmaline was co-administered, providing a quantitative assessment for the impact of concurrent MAOI harmaline on 5-MeO-DMT-induced hyperthermia. In addition, the hyperpyrexia caused by toxic dose combinations of harmaline and 5-MeO-DMT were linked to the increased systemic exposure to harmaline rather than 5-MeO-DMT, although the body temperature profiles were mispredicted by the model. The results indicate that current PK/PD model may be used as a new conceptual framework to define the impact of serotonergic agents and stress factors on thermoregulation.

  12. Alleviation of thermoregulatory dysfunction with the new serotonin and norepinephrine reuptake inhibitor desvenlafaxine succinate in ovariectomized rodent models.

    PubMed

    Deecher, Darlene C; Alfinito, Peter D; Leventhal, Liza; Cosmi, Scott; Johnston, Grace H; Merchenthaler, Istvan; Winneker, Richard

    2007-03-01

    Hot flushes and night sweats, referred to as vasomotor symptoms (VMS), are presumed to be a result of declining hormone levels and are the principal menopausal symptoms for which women seek medical treatment. To date, estrogens and/or some progestins are the most effective therapeutics for alleviating VMS; however, these therapies may not be appropriate for all women. Therefore, nonhormonal therapies are being evaluated. The present study investigated a new reuptake inhibitor, desvenlafaxine succinate (DVS), in animal models of temperature dysfunction. Both models used are based on measuring changes in tail-skin temperature (TST) in ovariectomized (OVX) rats. The first relies on naloxone-induced withdrawal in morphine-dependent (MD) OVX rats, resulting in an acute rise in TST. The second depends on an OVX-induced loss of TST decreases during the dark phase as measured by telemetry. An initial evaluation demonstrated abatement of the rise in TST with long-term administration of ethinyl estradiol or with a single oral dose of DVS (130 mg/kg) in the MD model. Further evaluation showed that orally administered DVS acutely and dose dependently (10-100 mg/kg) abated a naloxone-induced rise in TST of MD rats and alleviated OVX-induced temperature dysfunction in the telemetry model. Oral administration of DVS to OVX rats caused significant increases in serotonin and norepinephrine levels in the preoptic area of the hypothalamus, a key region of the brain involved in temperature regulation. These preclinical studies provide evidence that DVS directly impacts thermoregulatory dysfunction in OVX rats and may have utility in alleviating VMS associated with menopause.

  13. Simultaneous telemetric monitoring of tail-skin and core body temperature in a rat model of thermoregulatory dysfunction.

    PubMed

    Cosmi, Scott; Pawlyk, Aaron C; Alfinito, Peter D; Roman, Janet; Zhou, Tianhui; Deecher, Darlene C

    2009-04-15

    Temperature dysfunction, clinically described as hot flashes/flushes and night sweats, commonly occur in women transitioning through menopause. Research in this field has yet to fully elucidate the biological underpinnings explaining this dysfunction. The need to develop animal models that can be used to study hormone-dependent temperature regulation is essential to advancing this scientific area. Development of telemetric transmitters for monitoring tail-skin (TST) and core body (CBT) temperatures for animal research has increased the accuracy of data by reducing extraneous factors associated with previous methods. However, until recently, TST and CBT could not be simultaneously measured telemetrically within the same animal. In this report, new dual temperature monitoring transmitters were validated by simultaneously evaluating them with the single measurement transmitters using the ovariectomized (OVX) rat thermoregulatory dysfunction model. A major advantage of measuring TST and CBT in the same animal is the ability to relate temporal changes on these two temperature parameters. Comparative experimentation was performed by single administration of clonidine (alpha(2) adrenergic agonist), MDL-100907 (5-HT(2a) antagonist), or a 7-day treatment of 17alpha-ethinyl estradiol (EE). Clonidine caused decreases in TST and CBT, MDL-100907 caused increases in TST while decreasing CBT, and EE caused decreases in TST with minor CBT decreases only at the higher dose. Data from either probe type showed similar results on temperature parameters regardless of transmitter used. These findings support the use of the new dual temperature transmitters and should enhance the quality and interpretation of data being generated in thermoregulation studies.

  14. Modeling the finger instability in an expanding cell monolayer.

    PubMed

    Tarle, Victoria; Ravasio, Andrea; Hakim, Vincent; Gov, Nir S

    2015-10-01

    Collective motion occurs in many biological processes, such as wound healing, tumor invasion and embryogenesis. Experiments of cell monolayer migration have revealed the spontaneous formation of finger-like instabilities, with leader cells at their tips. We present a particle-based model for collective cell migration, based on several elements that have been found experimentally to influence cellular movement. Inside the bulk we include velocity alignment interactions between neighboring cells. At the border contour of the layer we introduce the following additional forces: surface-elasticity restoring force, curvature-dependent positive feedback, and contractile acto-myosin cables. We find that the curvature-driven instability at the layer edge is necessary and sufficient for the formation of cellular fingers, which are in good agreement with experimental observations.

  15. Review on modeling heat transfer and thermoregulatory responses in human body.

    PubMed

    Fu, Ming; Weng, Wenguo; Chen, Weiwang; Luo, Na

    2016-12-01

    Several mathematical models of human thermoregulation have been developed, contributing to a deep understanding of thermal responses in different thermal conditions and applications. In these models, the human body is represented by two interacting systems of thermoregulation: the controlling active system and the controlled passive system. This paper reviews the recent research of human thermoregulation models. The accuracy and scope of the thermal models are improved, for the consideration of individual differences, integration to clothing models, exposure to cold and hot conditions, and the changes of physiological responses for the elders. The experimental validated methods for human subjects and manikin are compared. The coupled method is provided for the manikin, controlled by the thermal model as an active system. Computational Fluid Dynamics (CFD) is also used along with the manikin or/and the thermal model, to evaluate the thermal responses of human body in various applications, such as evaluation of thermal comfort to increase the energy efficiency, prediction of tolerance limits and thermal acceptability exposed to hostile environments, indoor air quality assessment in the car and aerospace industry, and design protective equipment to improve function of the human activities.

  16. Thermoregulatory models of safety-for-flight issues for space operations

    NASA Astrophysics Data System (ADS)

    Pisacane, V. L.; Kuznetz, L. H.; Logan, J. S.; Clark, J. B.; Wissler, E. H.

    2006-10-01

    This study investigates the use of a mathematical model for thermoregulation as a tool in safety-of-flight issues and proposed solutions for mission operations of the Space Shuttle and the International Space Station. Specifically, this study assesses the effects of elevated cabin temperature and metabolic loads on astronauts wearing the Advanced Crew Escape Suit (ACES) and the Liquid Cooled Ventilation Garment (LCVG). The 225-node Wissler model is validated by comparison with two ground-based human subject tests, firefighters, and surrogate astronauts under anomalous conditions that show good agreement. Subsequent simulations indicate that the performance of the ACES/LCVG is marginal. Increases in either workload or cabin temperature from the nominal will increase rectal temperature, stored heat load, heart rate, and sweating leading to possible deficits in the ability of the astronauts to perform cognitive and motor tasks that could affect the safety of the mission, especially the safe landing of the Shuttle. Specific relationships are given between cabin temperature and metabolic rate that define the threshold for decreased manual dexterity and loss of tracking skills. Model results indicate that the most effective mitigation strategy would be to decrease the LCVG inlet temperature. Methods of accomplishing this are also proposed.

  17. A three-dimensional kinematic model of the human long finger and the muscles that actuate it.

    PubMed

    Biggs, J; Horch, K

    1999-11-01

    A kinematic model of the human long finger and the six muscles that actuate it is presented. The model transforms finger pose into estimates of muscle excursions and fingertip location. The effects of abduction/adduction about the metacarpo-phalangeal joint are accounted for, as are the effects of flexion of the three finger joints. A set of parameters are provided which approximate kinematics of the segments and muscles of a cadaver finger over the range of finger poses humans normally assume.

  18. Thermoregulatory responses to RF energy absorption.

    PubMed

    Adair, Eleanor R; Black, David R

    2003-01-01

    This white paper combines a tutorial on the fundamentals of thermoregulation with a review of the current literature concerned with physiological thermoregulatory responses of humans and laboratory animals in the presence of radio frequency (RF) and microwave fields. The ultimate goal of research involving whole body RF exposure of intact organisms is the prediction of effects of such exposure on human beings. Most of the published research on physiological thermoregulation has been conducted on laboratory animals, with a heavy emphasis on laboratory rodents. Because their physiological heat loss mechanisms are limited, these small animals are very poor models for human beings. Basic information about the thermoregulatory capabilities of animal models relative to human capability is essential for the appropriate evaluation and extrapolation of animal data to humans. In general, reliance on data collected on humans and nonhuman primates, however fragmentary, yields a more accurate understanding of how RF fields interact with humans. Such data are featured in this review, including data from both clinic and laboratory. Featured topics include thermal sensation, human RF overexposures, exposures attending magnetic resonance imaging (MRI), predictions based on simulation models, and laboratory studies of human volunteers. Supporting data from animal studies include the thermoregulatory profile, response thresholds, physiological responses of heat production and heat loss, intense or prolonged exposure, RF effects on early development, circadian variation, and additive drug-microwave interactions. The conclusion is inescapable that humans demonstrate far superior thermoregulatory ability over other tested organisms during RF exposure at, or even above current human exposure guidelines. Published 2003 Wiley-Liss, Inc.

  19. FINGERING CONVECTION AND CLOUDLESS MODELS FOR COOL BROWN DWARF ATMOSPHERES

    SciTech Connect

    Tremblin, P.; Amundsen, D. S.; Mourier, P.; Baraffe, I.; Chabrier, G.; Drummond, B.; Homeier, D.; Venot, O. E-mail: pascal.tremblin@cea.fr

    2015-05-01

    This work aims to improve the current understanding of the atmospheres of brown dwarfs, especially cold ones with spectral types T and Y, whose modeling is a current challenge. Silicate and iron clouds are believed to disappear at the photosphere at the L/T transition, but cloudless models fail to reproduce correctly the spectra of T dwarfs, advocating for the addition of more physics, e.g., other types of clouds or internal energy transport mechanisms. We use a one-dimensional radiative/convective equilibrium code ATMO to investigate this issue. This code includes both equilibrium and out-of-equilibrium chemistry and solves consistently the PT structure. Included opacity sources are H{sub 2}-H{sub 2}, H{sub 2}-He, H{sub 2}O, CO, CO{sub 2}, CH{sub 4}, NH{sub 3}, K, Na, and TiO, VO if they are present in the atmosphere. We show that the spectra of Y dwarfs can be accurately reproduced with a cloudless model if vertical mixing and NH{sub 3} quenching are taken into account. T dwarf spectra still have some reddening in, e.g., J–H, compared to cloudless models. This reddening can be reproduced by slightly reducing the temperature gradient in the atmosphere. We propose that this reduction of the stabilizing temperature gradient in these layers, leading to cooler structures, is due to the onset of fingering convection, triggered by the destabilizing impact of condensation of very thin dust.

  20. Structural model of ubiquitin transfer onto an artificial RING finger as an E3 ligase

    NASA Astrophysics Data System (ADS)

    Miyamoto, Kazuhide

    2014-10-01

    The artificial WSTF PHD_EL5 RING finger was designed via ``α-helical region substitution'', and its structural model for the attachment of activated ubiquitin has been demonstrated. Chemical modifications of Cys residues, the circular dichroism spectra, and substrate-independent ubiquitination assays illustrated that the WSTF PHD_EL5 RING finger has E3 activity, and it is ubiquitinated via Lys14. Homology modeling calculations revealed that the WSTF PHD_EL5 RING finger possesses a classical RING fold for specific E2-E3 binding. The docking poses of the WSTF PHD_EL5 RING finger with the UbcH5b-ubiquitin conjugate provided insight into its functional E2 interaction and development of ubiquitination at the atomic level. The structural model of the artificial WSTF PHD_EL5 RING finger proposed by the present work is useful and may help to extend the strategy of α-helical region substitution.

  1. Artefact-reduced kinematics measurement using a geometric finger model with mixture-prior particle filtering.

    PubMed

    Chang, Cheung-Wen; Kuo, Li-Chieh; Jou, I-Ming; Su, Fong-Chin; Sun, Yung-Nien

    2013-01-01

    It is challenging to measure the finger's kinematics of underlying bones in vivo. This paper presents a new method of finger kinematics measurement, using a geometric finger model and several markers deliberately stuck on skin surface. Using a multiple-view camera system, the optimal motion parameters of finger model were estimated using the proposed mixture-prior particle filtering. This prior, consisting of model and marker information, avoids generating improper particles for achieving near real-time performance. This method was validated using a planar fluoroscopy system that worked simultaneously with photographic system. Ten male subjects with asymptomatic hands were investigated in experiments. The results showed that the kinematic parameters could be estimated more accurately by the proposed method than by using only markers. There was 20-40% reduction in skin artefacts achieved for finger flexion/extension. Thus, this profile system can be developed as a tool of reliable kinematics measurement with good applicability for hand rehabilitation.

  2. Modeling of contact mechanics and friction limit surfaces for soft fingers in robotics, with experimental results

    SciTech Connect

    Xydas, N.; Kao, I.

    1999-09-01

    A new theory in contact mechanics for modeling of soft fingers is proposed to define the relationship between the normal force and the radius of contact for soft fingers by considering general soft-finger materials, including linearly and nonlinearly elastic materials. The results show that the radius of contact is proportional to the normal force raised to the power of {gamma}, which ranges from 0 to 1/3. This new theory subsumes the Hertzian contact model for linear elastic materials, where {gamma} = 1/3. Experiments are conducted to validate the theory using artificial soft fingers made of various materials such as rubber and silicone. Results for human fingers are also compared. This theory provides a basis for numerically constructing friction limit surfaces. The numerical friction limit surface can be approximated by an ellipse, with the major and minor axes as the maximum friction force and the maximum moment with respect to the normal axis of contact, respectively. Combining the results of the contact-mechanics model with the contact-pressure distribution, the normalized friction limit surface can be derived for anthropomorphic soft fingers. The results of the contact-mechanics model and the pressure distribution for soft fingers facilitate the construction of numerical friction limit surfaces, and will enable us to analyze and simulate contact behaviors of grasping and manipulation in robotics.

  3. Evidence evaluation in fingerprint comparison and automated fingerprint identification systems--Modeling between finger variability.

    PubMed

    Egli Anthonioz, N M; Champod, C

    2014-02-01

    In the context of the investigation of the use of automated fingerprint identification systems (AFIS) for the evaluation of fingerprint evidence, the current study presents investigations into the variability of scores from an AFIS system when fingermarks from a known donor are compared to fingerprints that are not from the same source. The ultimate goal is to propose a model, based on likelihood ratios, which allows the evaluation of mark-to-print comparisons. In particular, this model, through its use of AFIS technology, benefits from the possibility of using a large amount of data, as well as from an already built-in proximity measure, the AFIS score. More precisely, the numerator of the LR is obtained from scores issued from comparisons between impressions from the same source and showing the same minutia configuration. The denominator of the LR is obtained by extracting scores from comparisons of the questioned mark with a database of non-matching sources. This paper focuses solely on the assignment of the denominator of the LR. We refer to it by the generic term of between-finger variability. The issues addressed in this paper in relation to between-finger variability are the required sample size, the influence of the finger number and general pattern, as well as that of the number of minutiae included and their configuration on a given finger. Results show that reliable estimation of between-finger variability is feasible with 10,000 scores. These scores should come from the appropriate finger number/general pattern combination as defined by the mark. Furthermore, strategies of obtaining between-finger variability when these elements cannot be conclusively seen on the mark (and its position with respect to other marks for finger number) have been presented. These results immediately allow case-by-case estimation of the between-finger variability in an operational setting.

  4. Deficiency in adipocyte chemokine receptor CXCR4 exacerbates obesity and compromises thermoregulatory responses of brown adipose tissue in a mouse model of diet-induced obesity

    PubMed Central

    Yao, Longbiao; Heuser-Baker, Janet; Herlea-Pana, Oana; Zhang, Nan; Szweda, Luke I.; Griffin, Timothy M.; Barlic-Dicen, Jana

    2014-01-01

    The chemokine receptor CXCR4 is expressed on adipocytes and macrophages in adipose tissue, but its role in this tissue remains unknown. We evaluated whether deficiency in either adipocyte or myeloid leukocyte CXCR4 affects body weight (BW) and adiposity in a mouse model of high-fat-diet (HFD)-induced obesity. We found that ablation of adipocyte, but not myeloid leukocyte, CXCR4 exacerbated obesity. The HFD-fed adipocyte-specific CXCR4-knockout (AdCXCR4ko) mice, compared to wild-type C57BL/6 control mice, had increased BW (average: 52.0 g vs. 35.5 g), adiposity (average: 49.3 vs. 21.0% of total BW), and inflammatory leukocyte content in white adipose tissue (WAT), despite comparable food intake. As previously reported, HFD feeding increased uncoupling protein 1 (UCP1) expression (fold increase: 3.5) in brown adipose tissue (BAT) of the C57BL/6 control mice. However, no HFD-induced increase in UCP1 expression was observed in the AdCXCR4ko mice, which were cold sensitive. Thus, our study suggests that adipocyte CXCR4 limits development of obesity by preventing excessive inflammatory cell recruitment into WAT and by supporting thermogenic activity of BAT. Since CXCR4 is conserved between mouse and human, the newfound role of CXCR4 in mouse adipose tissue may parallel the role of this chemokine receptor in human adipose tissue.—Yao, L., Heuser-Baker, J., Herlea-Pana, O., Zhang, N., Szweda, L. I., Griffin, T. M., Barlic-Dicen, J. Deficiency in adipocyte chemokine receptor CXCR4 exacerbates obesity and compromises thermoregulatory responses of brown adipose tissue in a mouse model of diet-induced obesity. PMID:25016030

  5. Solitary granular avalanches: stability, fingering and theoretical modeling

    NASA Astrophysics Data System (ADS)

    Malloggi, Florent; Andreotti, Bruno; Clément, Eric; Aronson, Igor; Tsimring, Lev

    2008-03-01

    Avalanching processes do not only occur in the air as we know of snow avalanches, mud flows and land-slides. Such events frequently happen below the see level as they take many forms from turbidity currents to thick sediment waves. In this study we report results on laboratory scale avalanche experiments taking place both in the air and under-water. In both cases a family of stable solitary erosion/deposition waves is observed [1]. At higher inclination angles, we show the existence of a long wavelength transverse instability followed by a coarsening and the onset of a fingering pattern. While the experiments strongly differ by the spatial and time scales, the agreement between the stability diagrams, the wavelengths selection and the avalanche morphology suggest a common erosion/deposition scenario. We also use these erosion/deposition waves to investigate the dynamics of granular flow and jamming in the frame work of the Partial Fluidization Theory (PFT) proposed by Aronson et al. to describe the dynamics of granular matter near jamming [2]. [1] F. Malloggi et al. Europhysics Letters, 2006, Erosion waves: Transverse instabilities and fingering 75, 825-831 [2] I. S. Aranson et al.. Transverse instability of avalanches in granular flows down an incline. Physical Review E, 2006, 73, 050302; I.S.Aronson et al., Non rheological properties of granular flows: exploring the near jamming limit, preprint (2007).

  6. A probabilistic finger biodynamic model better depicts the roles of the flexors during unloaded flexion.

    PubMed

    Li, Kang; Zhang, Xudong

    2010-09-17

    Previous deterministic finger biomechanical models predicted that the flexor digitorum superficialis (FDS) was silent and the flexor digitorum profundus (FDP) was the only active flexor during finger flexion. Experimental studies in vivo, however, recorded activities of both flexors. In this study, in an attempt to elucidate the roles of the flexors, a probabilistic biodynamic model of the index finger was constructed to estimate the muscle-tendon forces during an experimentally measured index finger flexion movement. A Monte-Carlo simulation was performed with four model parameters, including moment arms, physiological cross sectional areas (PCSA), passive torques, and anthropometric measures as independent random variables. The muscle-tendon forces at each time point were determined using a nonlinear optimization technique. The model predicted that both FDS and FDP contributed to sustaining the movement and the FDS was not necessarily silent. The two distinct force patterns observed in vivo in experimental studies were also corroborated by the simulation. These findings, contrary to previous deterministic models' predictions but in agreement with experimental measurements, explained the observed coactivation of FDS and FDP, and resolved the controversy regarding the roles of the flexors in finger movement dynamics.

  7. [Study of mechanical effects of the EVA glove on finger base with finite element modeling].

    PubMed

    Li, Zhuoyou; Ding, Li; Yue, Guodong

    2013-08-01

    The hand strength of astronauts, when they are outside the space capsule, is highly influenced by the residual pressure (the pressure difference between inside pressure and outside one of the suit) of extravehicular activity spacesuit glove and the pressure exerted by braided fabric. The hand strength decreases significantly on extravehicular activity, severely reducing the operation efficiency. To measure mechanical influence caused by spacesuit glove on muscle-tendon and joints, the present paper analyzes the movement anatomy and biomechanical characteristics of gripping, and then proposes a grip model. With phalangeal joint simplified as hinges, seven muscles as a finger grip energy unit, the Hill muscle model was used to compute the effects. We also used ANSYS in this study to establish a 3-D finite element model of an index finger which included both bones and muscles with glove, and then we verified the model. This model was applied to calculate the muscle stress in various situations of bare hands or hands wearing gloves in three different sizes. The results showed that in order to achieve normal grip strength with the influence caused by superfluous press, the finger's muscle stress should be increased to 5.4 times of that in normal situation, with most of the finger grip strength used to overcome the influence of superfluous pressure. When the gap between the finger surface and the glove is smaller, the mechanical influence which superfluous press made will decrease. The results would provide a theoretical basis for the design of the EVA Glove.

  8. Scalability of the muscular action in a parametric 3D model of the index finger.

    PubMed

    Sancho-Bru, Joaquín L; Vergara, Margarita; Rodríguez-Cervantes, Pablo-Jesús; Giurintano, David J; Pérez-González, Antonio

    2008-01-01

    A method for scaling the muscle action is proposed and used to achieve a 3D inverse dynamic model of the human finger with all its components scalable. This method is based on scaling the physiological cross-sectional area (PCSA) in a Hill muscle model. Different anthropometric parameters and maximal grip force data have been measured and their correlations have been analyzed and used for scaling the PCSA of each muscle. A linear relationship between the normalized PCSA and the product of the length and breadth of the hand has been finally used for scaling, with a slope of 0.01315 cm(-2), with the length and breadth of the hand expressed in centimeters. The parametric muscle model has been included in a parametric finger model previously developed by the authors, and it has been validated reproducing the results of an experiment in which subjects from different population groups exerted maximal voluntary forces with their index finger in a controlled posture.

  9. Microwaves modify thermoregulatory behavior in squirrel monkey

    SciTech Connect

    Adair, E.R.; Adams, B.W.

    1980-01-01

    Squirrel monkeys (Saimiri sciureus) trained to regulate environmental temperature (Ta) behaviorally were exposed in the far field of a horn antenna to ten-minute periods of 2,450 MHz CW microwaves. Incident power density ranged from 1 to 22 mW/cm2. The corresponding specific absorption rate (SAR), derived from temperature increments in saline-filled styrofoam models, ranged from 0.15 to 3.25 W/kg. Controls included exposure to infrared radiation equivalent incident energy and no radiation exposure. Normal thermo-regulatory behavior produces tight control over environmental and body temperatures; most monkeys select a Ta of 34-36 degrees C. Ten-minute exposures to 2,450 MHz CW microwaves at an incident power density of 6-8 mW/cm2 stimulated all animals to select a lower Ta. This threshold energy represents a whole-body SAR of 1.1 W/kg, about 20% of the resting metabolic rate of the monkey. Thermoregulatory behavior was highly efficient, and skin and rectal temperatures remained stable, even at 22 mW/cm2 where the preferred Ta was lowered by as much as 4 degrees C. No comparable reduction in selected Ta below control levels occurred during exposure to infrared radiation of equal incident power density.

  10. Insights using the molecular model of Lipoxygenase from Finger millet (Eleusine coracana (L.))

    PubMed Central

    2016-01-01

    Lipoxygenase-1 (LOX-1) protein provides defense against pests and pathogens and its presence have been positively correlated with plant resistance against pathogens. Linoleate is a known substrate of lipoxygenase and it induces necrosis leading to the accumulation of isoflavonoid phytoalexins in plant leaves. Therefore, it is of interest to study the structural features of LOX-1 from Finger millet. However, the structure ofLOX-1 from Finger millet is not yet known. A homology model of LOX-1 from Finger millet is described. Domain architecture study suggested the presence of two domains namely PLAT (Phospho Lipid Acyl Transferase) and lipoxygenase. Molecular docking models of linoleate with lipoxygenase from finger millet, rice and sorghum are reported. The features of docked models showed that finger millet have higher pathogen resistance in comparison to other cereal crops. This data is useful for the molecular cloning of fulllength LOX-1 gene for validating its role in improving plant defense against pathogen infection and for various other biological processes. PMID:28149050

  11. Cortex inspired model for inverse kinematics computation for a humanoid robotic finger.

    PubMed

    Gentili, Rodolphe J; Oh, Hyuk; Molina, Javier; Reggia, James A; Contreras-Vidal, José L

    2012-01-01

    In order to approach human hand performance levels, artificial anthropomorphic hands/fingers have increasingly incorporated human biomechanical features. However, the performance of finger reaching movements to visual targets involving the complex kinematics of multi-jointed, anthropomorphic actuators is a difficult problem. This is because the relationship between sensory and motor coordinates is highly nonlinear, and also often includes mechanical coupling of the two last joints. Recently, we developed a cortical model that learns the inverse kinematics of a simulated anthropomorphic finger. Here, we expand this previous work by assessing if this cortical model is able to learn the inverse kinematics for an actual anthropomorphic humanoid finger having its two last joints coupled and controlled by pneumatic muscles. The findings revealed that single 3D reaching movements, as well as more complex patterns of motion of the humanoid finger, were accurately and robustly performed by this cortical model while producing kinematics comparable to those of humans. This work contributes to the development of a bioinspired controller providing adaptive, robust and flexible control of dexterous robotic and prosthetic hands.

  12. Cortex Inspired Model for Inverse Kinematics Computation for a Humanoid Robotic Finger

    PubMed Central

    Gentili, Rodolphe J.; Oh, Hyuk; Molina, Javier; Reggia, James A.; Contreras-Vidal, José L.

    2013-01-01

    In order to approach human hand performance levels, artificial anthropomorphic hands/fingers have increasingly incorporated human biomechanical features. However, the performance of finger reaching movements to visual targets involving the complex kinematics of multi-jointed, anthropomorphic actuators is a difficult problem. This is because the relationship between sensory and motor coordinates is highly nonlinear, and also often includes mechanical coupling of the two last joints. Recently, we developed a cortical model that learns the inverse kinematics of a simulated anthropomorphic finger. Here, we expand this previous work by assessing if this cortical model is able to learn the inverse kinematics for an actual anthropomorphic humanoid finger having its two last joints coupled and controlled by pneumatic muscles. The findings revealed that single 3D reaching movements, as well as more complex patterns of motion of the humanoid finger, were accurately and robustly performed by this cortical model while producing kinematics comparable to those of humans. This work contributes to the development of a bioinspired controller providing adaptive, robust and flexible control of dexterous robotic and prosthetic hands. PMID:23366569

  13. An expanded binding model for Cys2His2 zinc finger protein-DNA interfaces

    NASA Astrophysics Data System (ADS)

    Persikov, Anton V.; Singh, Mona

    2011-06-01

    Cys2His2 zinc finger (C2H2-ZF) proteins comprise the largest class of eukaryotic transcription factors. The 'canonical model' for C2H2-ZF protein-DNA interaction consists of only four amino acid-nucleotide contacts per zinc finger domain, and this model has been the basis for several efforts for computationally predicting and experimentally designing protein-DNA interfaces. Here, we perform a systematic analysis of structural and experimental binding data and find that, in addition to the canonical contacts, several other amino acid and base pair combinations frequently play a role in C2H2-ZF protein-DNA binding. We suggest an expansion of the canonical C2H2-ZF model to include one to three additional contacts, and show that computational approaches including these additional contacts improve predictions of DNA targets of zinc finger proteins.

  14. Finger Muscle Attachments for an OpenSim Upper-Extremity Model

    PubMed Central

    Lee, Jong Hwa; Asakawa, Deanna S.; Dennerlein, Jack T.; Jindrich, Devin L.

    2015-01-01

    We determined muscle attachment points for the index, middle, ring and little fingers in an OpenSim upper-extremity model. Attachment points were selected to match both experimentally measured locations and mechanical function (moment arms). Although experimental measurements of finger muscle attachments have been made, models differ from specimens in many respects such as bone segment ratio, joint kinematics and coordinate system. Likewise, moment arms are not available for all intrinsic finger muscles. Therefore, it was necessary to scale and translate muscle attachments from one experimental or model environment to another while preserving mechanical function. We used a two-step process. First, we estimated muscle function by calculating moment arms for all intrinsic and extrinsic muscles using the partial velocity method. Second, optimization using Simulated Annealing and Hooke-Jeeves algorithms found muscle-tendon paths that minimized root mean square (RMS) differences between experimental and modeled moment arms. The partial velocity method resulted in variance accounted for (VAF) between measured and calculated moment arms of 75.5% on average (range from 48.5% to 99.5%) for intrinsic and extrinsic index finger muscles where measured data were available. RMS error between experimental and optimized values was within one standard deviation (S.D) of measured moment arm (mean RMS error = 1.5 mm < measured S.D = 2.5 mm). Validation of both steps of the technique allowed for estimation of muscle attachment points for muscles whose moment arms have not been measured. Differences between modeled and experimentally measured muscle attachments, averaged over all finger joints, were less than 4.9 mm (within 7.1% of the average length of the muscle-tendon paths). The resulting non-proprietary musculoskeletal model of the human fingers could be useful for many applications, including better understanding of complex multi-touch and gestural movements. PMID:25853869

  15. Finger muscle attachments for an OpenSim upper-extremity model.

    PubMed

    Lee, Jong Hwa; Asakawa, Deanna S; Dennerlein, Jack T; Jindrich, Devin L

    2015-01-01

    We determined muscle attachment points for the index, middle, ring and little fingers in an OpenSim upper-extremity model. Attachment points were selected to match both experimentally measured locations and mechanical function (moment arms). Although experimental measurements of finger muscle attachments have been made, models differ from specimens in many respects such as bone segment ratio, joint kinematics and coordinate system. Likewise, moment arms are not available for all intrinsic finger muscles. Therefore, it was necessary to scale and translate muscle attachments from one experimental or model environment to another while preserving mechanical function. We used a two-step process. First, we estimated muscle function by calculating moment arms for all intrinsic and extrinsic muscles using the partial velocity method. Second, optimization using Simulated Annealing and Hooke-Jeeves algorithms found muscle-tendon paths that minimized root mean square (RMS) differences between experimental and modeled moment arms. The partial velocity method resulted in variance accounted for (VAF) between measured and calculated moment arms of 75.5% on average (range from 48.5% to 99.5%) for intrinsic and extrinsic index finger muscles where measured data were available. RMS error between experimental and optimized values was within one standard deviation (S.D) of measured moment arm (mean RMS error = 1.5 mm < measured S.D = 2.5 mm). Validation of both steps of the technique allowed for estimation of muscle attachment points for muscles whose moment arms have not been measured. Differences between modeled and experimentally measured muscle attachments, averaged over all finger joints, were less than 4.9 mm (within 7.1% of the average length of the muscle-tendon paths). The resulting non-proprietary musculoskeletal model of the human fingers could be useful for many applications, including better understanding of complex multi-touch and gestural movements.

  16. Cortical network modeling for inverse kinematic computation of an anthropomorphic finger.

    PubMed

    Gentili, Rodolphe J; Oh, Hyuk; Molina, Javier; Contreras-Vidal, José L

    2011-01-01

    The performance of reaching movements to visual targets requires complex kinematic mechanisms such as redundant, multijointed, anthropomorphic actuators and thus is a difficult problem since the relationship between sensory and motor coordinates is highly nonlinear. In this article, we present a neural model able to learn the inverse kinematics of a simulated anthropomorphic robot finger (ShadowHand™ finger) having four degrees of freedom while performing 3D reaching movements. The results revealed that this neural model was able to control accurately and robustly the finger when performing single 3D reaching movements as well as more complex patterns of motion while generating kinematics comparable to those observed in human. The long term goal of this research is to design a bio-mimetic controller providing adaptive, robust and flexible control of dexterous robotic/prosthetics hands.

  17. Cortical Network Modeling for Inverse Kinematic Computation of an Anthropomorphic Finger

    PubMed Central

    Gentili, Rodolphe J.; Oh, Hyuk; Molina, Javier; Contreras-Vidal, José L.

    2014-01-01

    The performance of reaching movements to visual targets requires complex kinematic mechanisms such as redundant, multijointed, anthropomorphic actuators and thus is a difficult problem since the relationship between sensory and motor coordinates is highly nonlinear. In this article, we present a neural model able to learn the inverse kinematics of a simulated anthropomorphic robot finger (ShadowHand™ finger) having four degrees of freedom while performing 3D reaching movements. The results revealed that this neural model was able to control accurately and robustly the finger when performing single 3D reaching movements as well as more complex patterns of motion while generating kinematics comparable to those observed in human. The long term goal of this research is to design a bio-mimetic controller providing adaptive, robust and flexible control of dexterous robotic/prosthetics hands. PMID:22256258

  18. Modifications to the steady-state 41-node thermoregulatory model including validation of the respiratory and diffusional water loss equations

    NASA Technical Reports Server (NTRS)

    1974-01-01

    After the simplified version of the 41-Node Stolwijk Metabolic Man Model was implemented on the Sigma 3 and UNIVAC 1110 computers in batch mode, it became desirable to make certain revisions. First, the availability of time-sharing terminals makes it possible to provide the capability and flexibility of conversational interaction between user and model. Secondly, recent physiological studies show the need to revise certain parameter values contained in the model. Thirdly, it was desired to make quantitative and accurate predictions of evaporative water loss for humans in an orbiting space station. The result of the first phase of this effort are reported.

  19. Zinc finger nuclease technology: advances and obstacles in modelling and treating genetic disorders.

    PubMed

    Jabalameli, Hamid Reza; Zahednasab, Hamid; Karimi-Moghaddam, Amin; Jabalameli, Mohammad Reza

    2015-03-01

    Zinc finger nucleases (ZFNs) are engineered restriction enzymes designed to target specific DNA sequences within the genome. Assembly of zinc finger DNA-binding domain to a DNA-cleavage domain enables the enzyme machinery to target unique locus in the genome and invoke endogenous DNA repair mechanisms. This machinery offers a versatile approach in allele editing and gene therapy. Here we discuss the architecture of ZFNs and strategies for generating targeted modifications within the genome. We review advances in gene therapy and modelling of the disease using these enzymes and finally, discuss the practical obstacles in using this technology. Copyright © 2014 Elsevier B.V. All rights reserved.

  20. Prediction and compensation by an internal model for back forces during finger opening in an overarm throw.

    PubMed

    Hore, J; Watts, S; Tweed, D

    1999-09-01

    Previous studies have indicated that timing of finger opening in an overarm throw is likely controlled centrally, possibly by means of an internal model of hand trajectory. The present objective was to extend the study of throwing to an examination of the dynamics of finger opening. Throwing a heavy ball and throwing a light ball presumably require different neural commands, because the weight of the ball affects the mechanics of the arm, and particularly, the mechanics of the finger. Yet finger control is critical to the accuracy of an overarm throw. We hypothesized that finger opening in an overarm throw is controlled by a central mechanism that uses an internal model to predict and compensate for movement-dependent back forces on the fingers. To test this idea we determined whether finger motion is affected by back forces, i.e., whether larger back forces cause larger finger extensions. Back forces were varied by having subjects throw, at the same fast speed, tennis-sized balls of different weights (14, 55, and 196 g). Arm- and finger-joint rotations were recorded with the search-coil technique; forces on the middle finger were measured with force transducers. Recordings showed that during ball release, the middle finger experienced larger back forces in throws with heavier balls. Nevertheless, most subjects showed proximal interphalangeal joint extensions that were unchanged or actually smaller with the heavier balls. This was the case for the first throw and for all subsequent throws with a ball of a new weight. This suggests that the finger flexors compensated for the larger back forces by exerting larger torques during finger extension. Supporting this view, at the moment of ball release, all finger joints flexed abruptly due to the now unopposed torques of the finger flexors, and the amplitude of this flexion was proportional to ball weight. We conclude that in overarm throws made with balls of different weights, the CNS predicts the different back forces

  1. Finger Thickening during Extra-Heavy Oil Waterflooding: Simulation and Interpretation Using Pore-Scale Modelling

    PubMed Central

    Bondino, Igor; Hamon, Gerald

    2017-01-01

    Although thermal methods have been popular and successfully applied in heavy oil recovery, they are often found to be uneconomic or impractical. Therefore, alternative production protocols are being actively pursued and interesting options include water injection and polymer flooding. Indeed, such techniques have been successfully tested in recent laboratory investigations, where X-ray scans performed on homogeneous rock slabs during water flooding experiments have shown evidence of an interesting new phenomenon–post-breakthrough, highly dendritic water fingers have been observed to thicken and coalesce, forming braided water channels that improve sweep efficiency. However, these experimental studies involve displacement mechanisms that are still poorly understood, and so the optimization of this process for eventual field application is still somewhat problematic. Ideally, a combination of two-phase flow experiments and simulations should be put in place to help understand this process more fully. To this end, a fully dynamic network model is described and used to investigate finger thickening during water flooding of extra-heavy oils. The displacement physics has been implemented at the pore scale and this is followed by a successful benchmarking exercise of the numerical simulations against the groundbreaking micromodel experiments reported by Lenormand and co-workers in the 1980s. A range of slab-scale simulations has also been carried out and compared with the corresponding experimental observations. We show that the model is able to replicate finger architectures similar to those observed in the experiments and go on to reproduce and interpret, for the first time to our knowledge, finger thickening following water breakthrough. We note that this phenomenon has been observed here in homogeneous (i.e. un-fractured) media: the presence of fractures could be expected to exacerbate such fingering still further. Finally, we examine the impact of several system

  2. Cold thermoregulatory responses following exertional fatigue.

    PubMed

    Castellani, John W; Sawka, Michael N; DeGroot, David W; Young, Andrew J

    2010-06-01

    Participants in prolonged, physically demanding cold-weather activities are at risk for a condition called "thermoregulatory fatigue". During cold exposure, the increased gradient favoring body heat loss to the environment is opposed by physiological responses and clothing and behavioral strategies that conserve body heat stores to defend body temperature. The primary human physiological responses elicited by cold exposure are shivering and peripheral vasoconstriction. Shivering increases thermogenesis and replaces body heat losses, while peripheral vasoconstriction improves thermal insulation of the body and retards the rate of heat loss. A body of scientific literature supports the concept that prolonged and/or repeated cold exposure, fatigue induced by sustained physical exertion, or both together, can impair the shivering and vasoconstrictor responses to cold ("thermoregulatory fatigue"). The mechanisms accounting for this thermoregulatory impairment are not clear, but there is evidence to suggest that changes in central thermoregulatory control or peripheral sympathetic responsiveness to cold lead to thermoregulatory fatigue and increased susceptibility to hypothermia.

  3. The BEM-FDM model of thermal processes proceeding in the domain of the human finger.

    PubMed

    Majchrzak, Ewa; Mochnacki, Bohdan; Tarasek, Damian; Dziewoński, Mirosław

    2015-01-01

    The problem of the numerical modeling of thermal processes proceeding in the non-homogeneous domain of the human finger is discussed. The domain considered constitutes the assembling of soft and bone tissues and the system of supplying blood vessels (arteries and veins). The mathematical description of the process analyzed corresponds to the so-called vascular models. At the stage of numerical modeling the algorithm being the composition of the boundary element method (BEM) and the finite difference method (FDM) is applied. The algorithm presented allows one to determine the steady state temperature field in the finger domain in natural convection conditions. To verify the effectiveness and exactness of the method of the problem solution, the thermal imaging measurements of the finger surface temperature have been done. The compatibility of numerical and experimental results (the natural convection conditions) has proved to be quite satisfactory. It is possible to use the algorithm proposed for the modeling of thermal processes proceeding in the conditions of low or high ambient temperatures and the big values of heat transfer coefficients. The impact of protective clothing on the temperature field in the domain of the finger can also be analyzed.

  4. An improved predictive recognition model for Cys(2)-His(2) zinc finger proteins.

    PubMed

    Gupta, Ankit; Christensen, Ryan G; Bell, Heather A; Goodwin, Mathew; Patel, Ronak Y; Pandey, Manishi; Enuameh, Metewo Selase; Rayla, Amy L; Zhu, Cong; Thibodeau-Beganny, Stacey; Brodsky, Michael H; Joung, J Keith; Wolfe, Scot A; Stormo, Gary D

    2014-04-01

    Cys(2)-His(2) zinc finger proteins (ZFPs) are the largest family of transcription factors in higher metazoans. They also represent the most diverse family with regards to the composition of their recognition sequences. Although there are a number of ZFPs with characterized DNA-binding preferences, the specificity of the vast majority of ZFPs is unknown and cannot be directly inferred by homology due to the diversity of recognition residues present within individual fingers. Given the large number of unique zinc fingers and assemblies present across eukaryotes, a comprehensive predictive recognition model that could accurately estimate the DNA-binding specificity of any ZFP based on its amino acid sequence would have great utility. Toward this goal, we have used the DNA-binding specificities of 678 two-finger modules from both natural and artificial sources to construct a random forest-based predictive model for ZFP recognition. We find that our recognition model outperforms previously described determinant-based recognition models for ZFPs, and can successfully estimate the specificity of naturally occurring ZFPs with previously defined specificities.

  5. A Linearized, Time Dependent Model of the Heat Transfer and Thermoregulatory Responses Occurring upon Immersion in Cold Water

    DTIC Science & Technology

    1982-03-01

    If an average thickness of the subcutaneous fat layer is determined from skinfold thickness measurements, then the conductivity of an individual’s...some 28 subjects, aged 8-20, whose subscapular skinfold thicknesses ranged from 5.0 mm to 19.2 mm, and whose weight ranged between 21 kg and 82 kg. They...the present model, the insulation values attributed to the subcutaneous fat mass were adjusted to 0.0057 m2 oC h/kcal per 1 mm of skinfold thickness

  6. Cold-Blooded Attention: Finger Temperature Predicts Attentional Performance.

    PubMed

    Vergara, Rodrigo C; Moënne-Loccoz, Cristóbal; Maldonado, Pedro E

    2017-01-01

    Thermal stress has been shown to increase the chances of unsafe behavior during industrial and driving performances due to reductions in mental and attentional resources. Nonetheless, establishing appropriate safety standards regarding environmental temperature has been a major problem, as modulations are also be affected by the task type, complexity, workload, duration, and previous experience with the task. To bypass this attentional and thermoregulatory problem, we focused on the body rather than environmental temperature. Specifically, we measured tympanic, forehead, finger and environmental temperatures accompanied by a battery of attentional tasks. We considered a 10 min baseline period wherein subjects were instructed to sit and relax, followed by three attentional tasks: a continuous performance task (CPT), a flanker task (FT) and a counting task (CT). Using multiple linear regression models, we evaluated which variable(s) were the best predictors of performance. The results showed a decrement in finger temperature due to instruction and task engagement that was absent when the subject was instructed to relax. No changes were observed in tympanic or forehead temperatures, while the environmental temperature remained almost constant for each subject. Specifically, the magnitude of the change in finger temperature was the best predictor of performance in all three attentional tasks. The results presented here suggest that finger temperature can be used as a predictor of alertness, as it predicted performance in attentional tasks better than environmental temperature. These findings strongly support that peripheral temperature can be used as a tool to prevent unsafe behaviors and accidents.

  7. Assessment of body mapping sportswear using a manikin operated in constant temperature mode and thermoregulatory model control mode

    NASA Astrophysics Data System (ADS)

    Wang, Faming; Del Ferraro, Simona; Molinaro, Vincenzo; Morrissey, Matthew; Rossi, René

    2014-09-01

    Regional sweating patterns and body surface temperature differences exist between genders. Traditional sportswear made from one material and/or one fabric structure has a limited ability to provide athletes sufficient local wear comfort. Body mapping sportswear consists of one piece of multiple knit structure fabric or of different fabric pieces that may provide athletes better wear comfort. In this study, the `modular' body mapping sportswear was designed and subsequently assessed on a `Newton' type sweating manikin that operated in both constant temperature mode and thermophysiological model control mode. The performance of the modular body mapping sportswear kit and commercial products were also compared. The results demonstrated that such a modular body mapping sportswear kit can meet multiple wear/thermal comfort requirements in various environmental conditions. All body mapping clothing (BMC) presented limited global thermophysiological benefits for the wearers. Nevertheless, BMC showed evident improvements in adjusting local body heat exchanges and local thermal sensations.

  8. Assessment of body mapping sportswear using a manikin operated in constant temperature mode and thermoregulatory model control mode.

    PubMed

    Wang, Faming; Del Ferraro, Simona; Molinaro, Vincenzo; Morrissey, Matthew; Rossi, René

    2014-09-01

    Regional sweating patterns and body surface temperature differences exist between genders. Traditional sportswear made from one material and/or one fabric structure has a limited ability to provide athletes sufficient local wear comfort. Body mapping sportswear consists of one piece of multiple knit structure fabric or of different fabric pieces that may provide athletes better wear comfort. In this study, the 'modular' body mapping sportswear was designed and subsequently assessed on a 'Newton' type sweating manikin that operated in both constant temperature mode and thermophysiological model control mode. The performance of the modular body mapping sportswear kit and commercial products were also compared. The results demonstrated that such a modular body mapping sportswear kit can meet multiple wear/thermal comfort requirements in various environmental conditions. All body mapping clothing (BMC) presented limited global thermophysiological benefits for the wearers. Nevertheless, BMC showed evident improvements in adjusting local body heat exchanges and local thermal sensations.

  9. Modeling gravity-driven fingering in rough-walled fractures using modified percolation theory

    SciTech Connect

    Glass, R.J.

    1992-12-31

    Pore scale invasion percolation theory is modified for imbibition of.wetting fluids into fractures. The effects of gravity, local aperture field geometry, and local in-plane air/water interfacial curvatureare included in the calculation of aperture filling potential which controls wetted structure growth within the fracture. The inclusion of gravity yields fingers oriented in the direction of the gravitational gradient. These fingers widen and tend to meander and branch more as the gravitational gradient decreases. In-plane interfacial curvature also greatly affects the wetted structure in both horizontal and nonhorizontal fractures causing the formation of macroscopic wetting fronts. The modified percolation model is used to simulate imbibition into an analogue rough-walled fracture where both fingering and horizontal imbibition experiments were previously conducted. Comparison of numerical and experimental results showed reasonably good agreement. This process oriented physical and numerical modeling is-a necessary step toward including gravity-driven fingering in models of flow and transport through unsaturated, fractured rock.

  10. Deterministic models for Laplacian growth of thin fingers in a Hele-Shaw geometry

    NASA Astrophysics Data System (ADS)

    Pecelerowicz, Michał; Szymczak, Piotr

    2014-05-01

    Laplacian growth is one of the fundamental mechanisms of pattern formation, driving such natural processes like electrodeposition, dielectric breakdown or viscous fingering. The characteristic features of these processes include a strong competition between spontaneously formed dendrite-like structures, and tip-splitting effects when dendrites bifurcate into secondary branches. Following Carleson and Makarov [1] we consider a simple, deterministic model of Laplacian growth, in which the growth takes place only at the tips of the long-and-thin fingers. The dynamics of the system can then be described by a deterministic Loewner equation. However, in contrast to [1], we allow the fingers to split, which is crucial to obtain the patterns corresponding to those observed in nature. We discuss different splitting criterions and study the dynamics of the model in variety of geometries including half-plane, channel, radial and the Hele-Shaw geometry. The latter is particularly relevant experimentally. In the Hele-Shaw cell, the pressure difference is imposed at two opposite ends of the system, whereas the two other boundaries are assumed to be reflecting. We derive the Loewner equation for this geometry (expressed in terms of elliptic functions) and study the tip-splitting dynamics in such a setting. In particular, we analyze in detail the tip-splitting cascade, triggered as the fingers approach the edge of the system. [1] L. Carleson and N. Makarov, J. Anal. Math. 87, 103 (2002).

  11. Experiments and Phase-field Modeling of Hydrate Growth at the Interface of Migrating Gas Fingers

    NASA Astrophysics Data System (ADS)

    Fu, X.; Jimenez-Martinez, J.; Porter, M. L.; Cueto-Felgueroso, L.; Juanes, R.

    2016-12-01

    The fate of methane bubbles escaping from seafloor seeps remains an important research question, as it directly concerns our understanding of the impact of seafloor methane leakage on ocean biogeochemistry. While the physics of rising bubbles in a water column has been studied extensively, the process is poorly understood when the gas bubbles form a hydrate ``crust" during their ascent. Understanding bubble rise, expansion and dissolution under these conditions is essential to determine the fate of bubble plumes of hydrate-forming gases such as methane and carbon dioxide from natural and man-made accidental releases. Here, we first present experimental observations of the dynamics of a bubble of Xenon in a water-filled and pressurized Hele-Shaw cell. The evolution is controlled by two processes: (1) the formation of a hydrate "crust" around the bubble, and (2) viscous fingering from bubble expansion (Figure 1). To reproduce the experimental observations, we propose a phase-field model that describes the nucleation and thickening of a porous solid shell on a moving gas-liquid interface. We design the free energy of the three-phase system (gas-liquid-hydrate) to rigorously account for interfacial effects, mutual solubility, and phase transformations (hydrate formation and disappearance). We introduce a pseudo-plasticity model with large viscosity variations to describe the plate-like rheology of the hydrate shell. We present high-resolution numerical simulations of the model, which illustrate the emergence of complex "crustal fingering" patterns as a result of gas fingering dynamics modulated by hydrate growth at the interface. Figure caption: Snapshot of the Hele-Shaw cell experiment. As the bubble expands from depressurization of the cell, gas fingers move through the liquid and Xe-hydrate readily forms at the gas-liquid interface, giving rise to complex "crustal fingering" patterns.

  12. Configuration of the thermal landscape determines thermoregulatory performance of ectotherms.

    PubMed

    Sears, Michael W; Angilletta, Michael J; Schuler, Matthew S; Borchert, Jason; Dilliplane, Katherine F; Stegman, Monica; Rusch, Travis W; Mitchell, William A

    2016-09-20

    Although most organisms thermoregulate behaviorally, biologists still cannot easily predict whether mobile animals will thermoregulate in natural environments. Current models fail because they ignore how the spatial distribution of thermal resources constrains thermoregulatory performance over space and time. To overcome this limitation, we modeled the spatially explicit movements of animals constrained by access to thermal resources. Our models predict that ectotherms thermoregulate more accurately when thermal resources are dispersed throughout space than when these resources are clumped. This prediction was supported by thermoregulatory behaviors of lizards in outdoor arenas with known distributions of environmental temperatures. Further, simulations showed how the spatial structure of the landscape qualitatively affects responses of animals to climate. Biologists will need spatially explicit models to predict impacts of climate change on local scales.

  13. Configuration of the thermal landscape determines thermoregulatory performance of ectotherms

    PubMed Central

    Sears, Michael W.; Angilletta, Michael J.; Schuler, Matthew S.; Borchert, Jason; Dilliplane, Katherine F.; Stegman, Monica; Rusch, Travis W.; Mitchell, William A.

    2016-01-01

    Although most organisms thermoregulate behaviorally, biologists still cannot easily predict whether mobile animals will thermoregulate in natural environments. Current models fail because they ignore how the spatial distribution of thermal resources constrains thermoregulatory performance over space and time. To overcome this limitation, we modeled the spatially explicit movements of animals constrained by access to thermal resources. Our models predict that ectotherms thermoregulate more accurately when thermal resources are dispersed throughout space than when these resources are clumped. This prediction was supported by thermoregulatory behaviors of lizards in outdoor arenas with known distributions of environmental temperatures. Further, simulations showed how the spatial structure of the landscape qualitatively affects responses of animals to climate. Biologists will need spatially explicit models to predict impacts of climate change on local scales. PMID:27601639

  14. Thermoregulatory sweat testing in patients with erythromelalgia.

    PubMed

    Davis, Mark D P; Genebriera, Joseph; Sandroni, Paola; Fealey, Robert D

    2006-12-01

    To examine the results of thermoregulatory sweat testing in patients with erythromelalgia and to compare them with the results of other neurophysiologic tests of small-fiber nerve function. Retrospective study. Tertiary referral center. Thirty-two consecutive patients with erythromelalgia who had thermoregulatory sweat testing in addition to vascular and nerve testing. The following information was abstracted for each patient: demographics, clinical presentation, and results of thermoregulatory sweat testing, vascular (noninvasive) testing, and nerve testing (electromyography and autonomic reflex screen, including quantitative sudomotor axon reflex test). Results of thermoregulatory sweat testing to evaluate small-fiber neuropathy, compared with other tools used to estimate small-fiber neuropathy. Thermoregulatory sweat testing results were abnormal in 28 (88%) of 32 patients, and quantitative sudomotor axon reflex test results were abnormal in 22 patients (69%). Abnormalities noted on thermoregulatory sweat testing varied from local hypohidrosis or anhidrosis to global anhidrosis. Global or almost-global anhidrosis was present in 8 patients (25%); in 19 patients (59%) the anhidrosis was distal, and 1 other patient (3%) had a less specific pattern of anhidrosis (multifocal or regional). The area of anhidrosis generally corresponded to the area that was symptomatic of the erythromelalgia. Small-fiber neuropathy is prevalent in most patients with erythromelalgia. Thermoregulatory sweat testing is a sensitive and useful marker of small-fiber neuropathy in these patients.

  15. Extension of the dielectric breakdown model for simulation of viscous fingering at finite viscosity ratios.

    PubMed

    Doorwar, Shashvat; Mohanty, Kishore K

    2014-07-01

    Immiscible displacement of viscous oil by water in a petroleum reservoir is often hydrodynamically unstable. Due to similarities between the physics of dielectric breakdown and immiscible flow in porous media, we extend the existing dielectric breakdown model to simulate viscous fingering patterns for a wide range of viscosity ratios (μ(r)). At low values of power-law index η, the system behaves like a stable Eden growth model and as the value of η is increased to unity, diffusion limited aggregation-like fractals appear. This model is compared with our two-dimensional (2D) experiments to develop a correlation between the viscosity ratio and the power index, i.e., η = 10(-5)μ(r)(0.8775). The 2D and three-dimensional (3D) simulation data appear scalable. The fingering pattern in 3D simulations at finite viscosity ratios appear qualitatively similar to the few experimental results published in the literature.

  16. Biodynamic modeling, system identification, and variability of multi-finger movements.

    PubMed

    Lee, Sang-Wook; Zhang, Xudong

    2007-01-01

    A forward dynamic model of human multi-fingered hand movement is proposed. The model represents digits 2-5 in manipulative acts as a 12-degrees-of-freedom (DOF) system, driven by torque actuators at individual joints and controlled using a parsimonious proportional-derivative (PD) scheme. The control parameters as feedback gains along with an auxiliary parameter to modulate the joint torque magnitudes and cross-coupling can be empirically identified in an iterative procedure minimizing the discrepancy between the model-prediction and measurement. The procedure is guided and computationally accelerated by pre-knowledge of relations between the parameters and kinematic responses. An empirical test based on real grasping movement data showed that the model simulated the multi-finger movements with varied inter-joint temporal coordination accurately: the grand mean of the root-mean-square-errors (RMSE) across trials performed by 28 subjects was 3.25 degrees . Analyses of the model parameters yielded new insights into intra- and inter-person variability in multi-finger movement performance, and distinguished the less variable motor control strategy from much more variable anthropometric and physiological factors.

  17. Saffman-Taylor fingering: why it is not a proper upscaled model of viscous fingering in a (even two-dimensional) random porous medium

    NASA Astrophysics Data System (ADS)

    Meheust, Y.; Toussaint, R.; Lovoll, G.; Maloy, K. J.

    2015-12-01

    P.G. Saffman & G. Taylor (1958) studied the stability of the interface between two immiscible fluids of different densities and viscosities when one displaces the other inside a Hele-Shaw (HS) cell. They showed that with a horizontal cell and if the displaced fluid is the more viscous, the interface is unstable and leads to a viscous fingering which they nearly fully modeled [1]. The HS geometry was introduced as a geometry imposing the same flow behavior as the Darcy-scale flow in a two-dimensional (2D) porous medium, and therefore allowing an analogy between the two configurations. This is however not obvious, since capillary forces act at very different scales in the two. Later, researchers performing unstable displacement experiments in HS cells containing random 2D porous media also observed viscous fingering at large viscosity ratios, but with invasion patterns very different from those of Saffman and Taylor (ST) [2-3]. It was however considered that the two processes were both Laplacian growth processes, i.e., processes in which the invasion probability density is proportional to the pressure gradient. Ten years ago, we investigated viscously-unstable drainage in 2D porous media experimentally and measured the growth activity as well as occupation probability maps for the invasion process [4-5]. We concluded that in viscous fingering in 2D porous media, the activity was rather proportional to the square of the pressure gradient magnitude (a so-called DBM model of exponent 2), so that the universality class of the growth/invasion process was different from that of ST viscous fingering. We now strengthen our claim with new results based on the comparison of (i) pressure measurements with the pressure field around a finger such as described by the ST analytical model, and (ii) branching angles in the invasion patterns with those expected for DBMs of various exponents. [1] Saffman, P. G. and Taylor, G. Proc. Soc. London 1958(Ser A 245), 312-329. [2] Lenormand, R

  18. Quantification of finger joint loadings using musculoskeletal modelling clarifies mechanical risk factors of hand osteoarthritis.

    PubMed

    Goislard de Monsabert, Benjamin; Vigouroux, Laurent; Bendahan, David; Berton, Eric

    2014-02-01

    Owing to limited quantitative data related to the loadings (forces and pressures) acting upon finger joints, several clinical observations regarding mechanical risk factors of hand osteoarthritis remain misunderstood. To improve the knowledge of this pathology, the present study used musculoskeletal modelling to quantify the forces and pressures acting upon hand joints during two grasping tasks. Kinematic and grip force data were recorded during both a pinch and a power grip tasks. Three-dimensional magnetic resonance imaging measurements were conducted to quantify joint contact areas. Using these datasets as input, a musculoskeletal model of the hand and wrist, including twenty-three degrees of freedom and forty-two muscles, has been developed to estimate joint forces and joint pressures. When compared with the power grip task, the pinch grip task resulted in two to eight times higher joint loadings whereas the grip forces exerted on each finger were twice lower. For both tasks, joint forces and pressures increased along a disto-proximal direction for each finger. The quantitative dataset provided by the present hand model clarified two clinical observations about osteoarthritis development which were not fully understood, i.e., the strong risk associated to pinch grip tasks and the high frequency of thumb-base osteoarthritis. Copyright © 2013 IPEM. Published by Elsevier Ltd. All rights reserved.

  19. Electrical imaging and fluid modeling of convective fingering in a shallow water-table aquifer

    NASA Astrophysics Data System (ADS)

    Dam, Remke L.; Eustice, Brian P.; Hyndman, David W.; Wood, Warren W.; Simmons, Craig T.

    2014-02-01

    Unstable density-driven flow can lead to enhanced solute transport in groundwater. Only recently has the complex fingering pattern associated with free convection been documented in field settings. Electrical resistivity (ER) tomography has been used to capture a snapshot of convective instabilities at a single point in time, but a thorough transient analysis is still lacking in the literature. We present the results of a 2 year experimental study at a shallow aquifer in the United Arab Emirates that was designed to specifically explore the transient nature of free convection. ER tomography data documented the presence of convective fingers following a significant rainfall event. We demonstrate that the complex fingering pattern had completely disappeared a year after the rainfall event. The observation is supported by an analysis of the aquifer halite budget and hydrodynamic modeling of the transient character of the fingering instabilities. Modeling results show that the transient dynamics of the gravitational instabilities (their initial development, infiltration into the underlying lower-density groundwater, and subsequent decay) are in agreement with the timing observed in the time-lapse ER measurements. All experimental observations and modeling results are consistent with the hypothesis that a dense brine that infiltrated into the aquifer from a surficial source was the cause of free convection at this site, and that the finite nature of the dense brine source and dispersive mixing led to the decay of instabilities with time. This study highlights the importance of the transience of free convection phenomena and suggests that these processes are more rapid than was previously understood.

  20. Modeling the finger joint moments in a hand at the maximal isometric grip: the effects of friction.

    PubMed

    Wu, John Z; Dong, Ren G; McDowell, Thomas W; Welcome, Daniel E

    2009-12-01

    The interaction between the handle and operator's hand affects the comfort and safety of tool and machine operations. In most of the previous studies, the investigators considered only the normal contact forces. The effect of friction on the joint moments in fingers has not been analyzed. Furthermore, the observed contact forces have not been linked to the internal musculoskeletal loading in the previous experimental studies. In the current study, we proposed a universal model of a hand to evaluate the joint moments in the fingers during grasping tasks. The hand model was developed on the platform of the commercial software package AnyBody. Only four fingers (index, long, ring, and little finger) were included in the model. The anatomical structure of each finger is comprised of four phalanges (distal, middle, proximal, and metacarpal phalange). The simulations were performed using an inverse dynamics technique. The joint angles and the normal contact forces on each finger section reported by previous researchers were used as inputs, while the joint moments of each finger were predicted. The predicted trends of the dependence of the distal interphalangeal (DIP) and proximal interphalangeal (PIP) joint moments on the cylinder diameter agree with those of the contact forces on the fingers observed in the previous experimental study. Our results show that the DIP and PIP joint moments reach their maximums at a cylinder diameter of about 31mm, which is consistent with the trend of the finger contact forces measured in the experiments. The proposed approach will be useful for simulating musculoskeletal loading in the hand for occupational activities, thereby optimizing tool-handle design.

  1. Modeling the frictional interaction in the tendon-pulley system of the human finger for use in robotics.

    PubMed

    Dermitzakis, Konstantinos; Morales, Marco Roberto; Schweizer, Andreas

    2013-01-01

    Physiological studies of the human finger indicate that friction in the tendon-pulley system accounts for a considerable fraction of the total output force (9-12%) in a high-load static posteccentric configuration. Such a phenomenon can be exploited for robotic and prosthetic applications, as it can result in (1) an increase of output force or (2) a reduction of energy consumption and actuator weight. In this study, a simple frictional, two-link, one-degree-of-freedom model of a human finger was created. The model is validated against in vitro human finger data, and its behavior is examined with respect to select physiological parameters. The results point to clear benefits of incorporating friction in tendon-driven robotic fingers for actuator mass and output force. If it is indeed the case that the majority of high-load hand grasps are posteccentric, there is a clear benefit of incorporating friction in tendon-driven prosthetic hand replacements.

  2. A cortically-inspired model for inverse kinematics computation of a humanoid finger with mechanically coupled joints.

    PubMed

    Gentili, Rodolphe J; Oh, Hyuk; Kregling, Alissa V; Reggia, James A

    2016-05-19

    The human hand's versatility allows for robust and flexible grasping. To obtain such efficiency, many robotic hands include human biomechanical features such as fingers having their two last joints mechanically coupled. Although such coupling enables human-like grasping, controlling the inverse kinematics of such mechanical systems is challenging. Here we propose a cortical model for fine motor control of a humanoid finger, having its two last joints coupled, that learns the inverse kinematics of the effector. This neural model functionally mimics the population vector coding as well as sensorimotor prediction processes of the brain's motor/premotor and parietal regions, respectively. After learning, this neural architecture could both overtly (actual execution) and covertly (mental execution or motor imagery) perform accurate, robust and flexible finger movements while reproducing the main human finger kinematic states. This work contributes to developing neuro-mimetic controllers for dexterous humanoid robotic/prosthetic upper-extremities, and has the potential to promote human-robot interactions.

  3. Development of a kinematic model to predict finger flexor tendon and subsynovial connective tissue displacement in the carpal tunnel.

    PubMed

    Kociolek, Aaron M; Keir, Peter J

    2015-01-01

    Finger flexor tendinopathies and carpal tunnel syndrome are histologically characterised by non-inflammatory fibrosis of the subsynovial connective tissue (SSCT) in the carpal tunnel, which is indicative of excessive and repetitive shear forces between the finger flexor tendons and SSCT. We assessed flexor digitorum superficialis (FDS) tendon and adjacent SSCT displacements with colour Doppler ultrasound as 16 healthy participants completed long finger flexion/extension movements captured by a motion capture system. FDS tendon displacements fit a second-order regression model based on metacarpophalangeal and proximal interphalangeal joint flexion angles (R(2) = 0.92 ± 0.01). SSCT displacements were 33.6 ± 1.7% smaller than FDS tendon displacements and also fit a second-order regression model (R(2) = 0.89 ± 0.01). FDS tendon and SSCT displacement both correlated with finger joint thickness, enabling participant-specific anthropometric scaling. We propose the current regression models as an ergonomic method to determine relative displacements between the finger flexor tendons and SSCT. Relative displacements between the finger flexor tendons and SSCT provide insight into gliding and friction in the carpal tunnel. Our regression models represent a move towards mechanistic-based ergonomic risk assessment of the wrist/hand. This is a natural evolution of ergonomic methods based on tendon-joint interaction.

  4. Histaminergic neurons in the hypothalamic thermoregulatory pathways

    SciTech Connect

    Lomax, P.; Green, M.D.

    1981-11-01

    Based on neurochemical and neurophysiological research, especially over the past decade, considerable evidence exists for accepting histamine as a central neurotransmitter alongside the other neuroamines. The data supporting a functional role are not complete, but they do exhibit a consistent pattern in the case of the central thermoregulatory pathways. Thus, the region of the thermoregulatory centers in the rostral hypothalamus contains relatively high concentrations of histamine and the enzyme systems for its synthesis and degradation: degeneration studies indicate histaminergic pathways in the hypothalamus; thermoregulatory changes can be induced by activation of either H/sub 1/ or H/sub 2/ receptors; behavioral studies reveal different functional roles for H/sub 1/ and H/sub 2/ receptors; and the thermoregulatory responses to histamine are detectable across different species, even in nonhomeothermic animals. This evidence supports assigning a transmitter function to histamine in the central thermoregulatory pathways that would appear to be as well-founded as the comparable data amassed for other neuroamines.

  5. Electrical Resistivity Imaging and Hydrodynamic Modeling of Convective Fingering in a Sabkha Aquifer

    NASA Astrophysics Data System (ADS)

    Van Dam, Remke; Eustice, Brian; Hyndman, David; Wood, Warren; Simmons, Craig

    2014-05-01

    Free convection, or fluid motion driven by density differences, is an important groundwater flow mechanism that can enhance transport and mixing of heat and solutes in the subsurface. Various issues of environmental and societal relevance are exacerbated convective mixing; it has been studied in the context of dense contaminant plumes, nuclear waste disposal, greenhouse gas sequestration, the impacts of sea level rise and saline intrusion on drinking water resources. The basic theory behind convective flow in porous media is well understood, but important questions regarding this process in natural systems remain unanswered. Most previous research on this topic has focused on theory and modeling, with only limited attention to experimental studies and field measurements. The few published studies present single snapshots, making it difficult to quantify transient changes in these systems. Non-invasive electrical methods have the potential to exploit the relation between solute concentrations and electrical conductance of a fluid, and thereby estimate fluid salinity differences in time and space. We present the results of a two-year experimental study at a shallow sabkha aquifer in the United Arab Emirates, about 50 km southwest of the city of Abu Dhabi along the coast of the Arabian Gulf, that was designed to explore the transient nature of free convection. Electrical resistivity tomography (ERT) data documented the presence of convective fingers following a significant rainfall event. One year later, the complex fingering pattern had completely disappeared. This observation is supported by analysis of the aquifer solute budget as well as hydrodynamic modeling of the system. The transient dynamics of the gravitational instabilities in the modeling results are in agreement with the timing observed in the time-lapse ERT data. Our experimental observations and modeling are consistent with the hypothesis that the instabilities arose from a dense brine that infiltrated

  6. ZFNGenome: A comprehensive resource for locating zinc finger nuclease target sites in model organisms

    PubMed Central

    2011-01-01

    Background Zinc Finger Nucleases (ZFNs) have tremendous potential as tools to facilitate genomic modifications, such as precise gene knockouts or gene replacements by homologous recombination. ZFNs can be used to advance both basic research and clinical applications, including gene therapy. Recently, the ability to engineer ZFNs that target any desired genomic DNA sequence with high fidelity has improved significantly with the introduction of rapid, robust, and publicly available techniques for ZFN design such as the Oligomerized Pool ENgineering (OPEN) method. The motivation for this study is to make resources for genome modifications using OPEN-generated ZFNs more accessible to researchers by creating a user-friendly interface that identifies and provides quality scores for all potential ZFN target sites in the complete genomes of several model organisms. Description ZFNGenome is a GBrowse-based tool for identifying and visualizing potential target sites for OPEN-generated ZFNs. ZFNGenome currently includes a total of more than 11.6 million potential ZFN target sites, mapped within the fully sequenced genomes of seven model organisms; S. cerevisiae, C. reinhardtii, A. thaliana, D. melanogaster, D. rerio, C. elegans, and H. sapiens and can be visualized within the flexible GBrowse environment. Additional model organisms will be included in future updates. ZFNGenome provides information about each potential ZFN target site, including its chromosomal location and position relative to transcription initiation site(s). Users can query ZFNGenome using several different criteria (e.g., gene ID, transcript ID, target site sequence). Tracks in ZFNGenome also provide "uniqueness" and ZiFOpT (Zinc Finger OPEN Targeter) "confidence" scores that estimate the likelihood that a chosen ZFN target site will function in vivo. ZFNGenome is dynamically linked to ZiFDB, allowing users access to all available information about zinc finger reagents, such as the effectiveness of a given

  7. Microwave challenges to the thermoregulatory system

    SciTech Connect

    Adair, E.R.

    1988-01-01

    The results of several kinds of experiments have been introduced as evidence in support of the thesis that the thermoregulatory system of endotherms functions no differently in the presence of microwaves than it does in the presence of conventional sources of thermal energy. The thermoregulatory profile, unique for each species, provides the framework for the argument. The results of our experiments have demonstrated the equivalence between T and microwave intensity as they influence individual responses of heat production and heat loss. This equivalence, in turn, allows the prediction of specific alterations in thermoregulatory responses when microwaves are present. Predictions of this kind are possible because the hierarchy of autonomic responses available to any given species is always the same. This fact should provide some comfort to those who profess concern abut the uniqueness of absorbed radiofrequency energy and its fate within the body. Additional comfort can be derived from the demonstration that changes in thermoregulatory responses in the presence of microwaves depend upon the integral of energy absorption by the whole body, not upon energy deposited in some restricted locus such as the PO/AH. It is clear that the circulatory system plays a major role in the distribution of energy deposited during such exposures, a fact already emphasized by others. This fact does not negate the presence of electrical hotspots as predicted on theoretical grounds or as demonstrated dosimetrically, but it does deemphasize their importance as potential deterrents to the efficient mobilization of thermoregulatory responses. The utility of the thermoregulatory profile in research of the kind described here cannot be overemphasized. 26 references.

  8. Mathematically modelling the effects of pacing, finger strategies and urgency on numerical typing performance with queuing network model human processor.

    PubMed

    Lin, Cheng-Jhe; Wu, Changxu

    2012-01-01

    Numerical typing is an important perceptual-motor task whose performance may vary with different pacing, finger strategies and urgency of situations. Queuing network-model human processor (QN-MHP), a computational architecture, allows performance of perceptual-motor tasks to be modelled mathematically. The current study enhanced QN-MHP with a top-down control mechanism, a close-loop movement control and a finger-related motor control mechanism to account for task interference, endpoint reduction, and force deficit, respectively. The model also incorporated neuromotor noise theory to quantify endpoint variability in typing. The model predictions of typing speed and accuracy were validated with Lin and Wu's (2011) experimental results. The resultant root-mean-squared errors were 3.68% with a correlation of 95.55% for response time, and 35.10% with a correlation of 96.52% for typing accuracy. The model can be applied to provide optimal speech rates for voice synthesis and keyboard designs in different numerical typing situations. An enhanced QN-MHP model was proposed in the study to mathematically account for the effects of pacing, finger strategies and internalised urgency on numerical typing performance. The model can be used to provide optimal pacing for voice synthesise systems and suggested optimal numerical keyboard designs under urgency.

  9. Hidden Markov model and support vector machine based decoding of finger movements using electrocorticography

    NASA Astrophysics Data System (ADS)

    Wissel, Tobias; Pfeiffer, Tim; Frysch, Robert; Knight, Robert T.; Chang, Edward F.; Hinrichs, Hermann; Rieger, Jochem W.; Rose, Georg

    2013-10-01

    Objective. Support vector machines (SVM) have developed into a gold standard for accurate classification in brain-computer interfaces (BCI). The choice of the most appropriate classifier for a particular application depends on several characteristics in addition to decoding accuracy. Here we investigate the implementation of hidden Markov models (HMM) for online BCIs and discuss strategies to improve their performance. Approach. We compare the SVM, serving as a reference, and HMMs for classifying discrete finger movements obtained from electrocorticograms of four subjects performing a finger tapping experiment. The classifier decisions are based on a subset of low-frequency time domain and high gamma oscillation features. Main results. We show that decoding optimization between the two approaches is due to the way features are extracted and selected and less dependent on the classifier. An additional gain in HMM performance of up to 6% was obtained by introducing model constraints. Comparable accuracies of up to 90% were achieved with both SVM and HMM with the high gamma cortical response providing the most important decoding information for both techniques. Significance. We discuss technical HMM characteristics and adaptations in the context of the presented data as well as for general BCI applications. Our findings suggest that HMMs and their characteristics are promising for efficient online BCIs.

  10. Changes in Thermoregulatory Behavior during Microwave Irradiation,

    DTIC Science & Technology

    Voluntary behavioral action is an organism’s first defense against exogenous thermal challenge. Endotherms and ectotherms alike use behavioral...level. For ectothermic species, these behaviors represent most of the thermoregulatory response available to the organism. For endothermic species, these

  11. Observations and modeling of surf zone transverse finger bars at the Gold Coast, Australia

    NASA Astrophysics Data System (ADS)

    Ribas, F.; Doeschate, A. ten; de Swart, H. E.; Ruessink, B. G.; Calvete, D.

    2014-08-01

    The occurrence and characteristics of transverse finger bars at Surfers Paradise (Gold Coast, Australia) have been quantified with 4 years of time-exposure video images. These bars are attached to the inner terrace and have an oblique orientation with respect to the coastline. They are observed during 24 % of the study period, in patches up to 15 bars, with an average lifetime of 5 days and a mean wavelength of 32 m. The bars are observed during obliquely incident waves of intermediate heights. Bar crests typically point toward the incoming wave direction, i.e., they are up-current oriented. The most frequent beach state when bars are present (43 % of the time) is a rhythmic low-tide terrace and an undulating outer bar. A morphodynamic model, which describes the feedback between waves, currents, and bed evolution, has been applied to study the mechanisms for finger bar formation. Realistic positive feedback leading to the formation of the observed bars only occurs if the sediment resuspension due to roller-induced turbulence is included. This causes the depth-averaged sediment concentration to decrease in the seaward direction, enhancing the convergence of sediment transport in the offshore-directed flow perturbations that occur over the up-current bars. The longshore current strength also plays an important role; the offshore root-mean-square wave height and angle must be larger than some critical values (0.5 m and 20∘, respectively, at 18-m depth). Model-data comparison indicates that the modeled bar shape characteristics (up-current orientation) and the wave conditions leading to the bar formation agree with data, while the modeled wavelengths and migration rates are larger than the observed ones. The discrepancies might be because in the model we neglect the influence of the large-scale beach configuration.

  12. Thermoregulatory responses to preoptic cooling in unrestrained rabbits

    NASA Technical Reports Server (NTRS)

    Mcewen, G. N., Jr.; Heath, J. E.

    1974-01-01

    Rabbits at ambient temperatures within the thermal neutral zone show two different metabolic responses to preoptic cooling. One response type is defined by a preoptic thermal sensitivity that shifts with ambient temperature and a 'set point' that remains constant. The other response type is defined by a set point that shifts with ambient temperature and a preoptic thermal sensitivity that remains constant. Both response types can be modeled by a single equation. Nonmetabolic thermoregulatory responses are not significantly different between the two response types.

  13. Thermoregulatory responses to preoptic cooling in unrestrained rabbits

    NASA Technical Reports Server (NTRS)

    Mcewen, G. N., Jr.; Heath, J. E.

    1974-01-01

    Rabbits at ambient temperatures within the thermal neutral zone show two different metabolic responses to preoptic cooling. One response type is defined by a preoptic thermal sensitivity that shifts with ambient temperature and a 'set point' that remains constant. The other response type is defined by a set point that shifts with ambient temperature and a preoptic thermal sensitivity that remains constant. Both response types can be modeled by a single equation. Nonmetabolic thermoregulatory responses are not significantly different between the two response types.

  14. Development and validation of a biodynamic model for predicting multi-finger movements in cylinder-grasping tasks.

    PubMed

    Lee, Sang Wook; Zhang, Xudong

    2009-03-01

    This article describes the development and validation of a model for predicting multi-finger movements in grasping activities. The model builds upon a newly proposed approach that incorporates forward dynamics and a system identification procedure, and is amenable to empirical tests. A database of multi-fingered grasping movements performed by 28 subjects was established and divided into four sets, one for model development and three for model validation. In the development phase, model parameter values were estimated by the iterative system identification procedure through a physics-based heuristic algorithm. The estimated parameter values were then statistically synthesised and integrated into the prediction model. In the validation phase, the model was applied to three novel datasets containing different grasping movements involving objects of varied sizes and different subjects. The results demonstrated the model's ability to predict hand prehensile movements with error magnitudes comparable to the inter-person variability in performing such movements. New insights into the control of multi-fingered hand prehensile movements at the systems and joint levels emerged from the model development and validation process. The current study contributes to building a foundation for long-term development of realistic biodynamic simulation of multi-finger hand movements. Such simulation capabilities will aid in design of hand-operated tools, devices or hand-intensive work for proactive ergonomics and in evaluation as well as treatment of functional impairment of the hand.

  15. A reduced model for salt-fingering convection in the small Lewis number limit

    NASA Astrophysics Data System (ADS)

    Xie, Jin-Han; Knobloch, Edgar

    2016-11-01

    We derive a reduced model that captures key features of salt-fingering convection, including secondary instabilities, in the asymptotic limit of small Lewis number and large flux ratio. In the infinite Prandtl number limit, this model combines a prognostic equation for the evolution of the salinity field with a novel diagnostic relation between the streamfunction and salinity. When the salinity and temperature Rayleigh numbers RaS and RaT are large, simulations reveal the existence of statistically steady saturated states, characterized by fluxes and kinetic energy that scale as powers of (RaS / RaT) - 1 . Three distinguished regimes are identified: a weakly nonlinear regime and two strongly nonlinear regimes characterized by distinct exponents. The processes responsible for saturation are described in detail and the probability density function of the saturated fields is determined. This work was supported by the National Science Foundation under Grant No. DMS-1317666.

  16. Modeling of interaction between a three-fingered surgical grasper and human spleen.

    PubMed

    Tirehdast, Mojdeh; Mirbagheri, Alireza; Asghari, Mohsen; Farahmand, Farzam

    2011-01-01

    The aim of this study was to develop a more sophisticated model of the spleen tissue and investigate its interactions with a three-fingered laparoscopic grasper. The spleen tissue, modeled as a hyper viscoelastic material, was subjected to external loadings, imposed by rigid grasping jaws. The tissue deformation as well as the sliding occurrence between tissue and jaws was investigated using nonlinear finite element method. Results indicated that a grasping configuration which aimed a sufficiently large piece of spleen with small radius of curvature was more successful for effective grasping. The trends and magnitudes of the tool-tissue interaction forces obtained during effective and ineffective grasping were quite different. A force with progressively increasing trend toward a high magnitude was found to be indicative of effective and safe grasping. This finding might be used to predict the effectiveness of different grasping configurations and sliding thresholds during spleen and other soft organs surgery.

  17. Decoding dexterous finger movements in a neural prosthesis model approaching real-world conditions.

    PubMed

    Egan, Joshua; Baker, Justin; House, Paul A; Greger, Bradley

    2012-11-01

    Dexterous finger movements can be decoded from neuronal action potentials acquired from a nonhuman primate using a chronically implanted Utah Electrode Array. We have developed an algorithm that can, after training, detect and classify individual and combined finger movements without any a priori knowledge of the data, task, or behavior. The algorithm is based on changes in the firing rates of individual neurons that are tuned for one or more finger movement types. Nine different movement types, which consisted of individual flexions, individual extensions, and combined flexions of the thumb, index finger, and middle finger, were decoded. The algorithm performed reliably on data recorded continuously during movement tasks, including a no-movement state, with an overall average sensitivity and specificity that were both > 92%. These results demonstrate a viable algorithm for decoding dexterous finger movements under conditions similar to those required for a real-world neural prosthetic application.

  18. The Electronic Behavior of Zinc-Finger Protein Binding Sites in the Context of the DNA Extended Ladder Model

    NASA Astrophysics Data System (ADS)

    Oiwa, Nestor; Cordeiro, Claudette; Heermann, Dieter

    2016-05-01

    Instead of ATCG letter alignments, typically used in bioinformatics, we propose a new alignment method using the probability distribution function of the bottom of the occupied molecular orbital (BOMO), highest occupied molecular orbital (HOMO) and lowest unoccupied orbital (LUMO). We apply the technique to transcription factors with Cys2His2 zinc fingers. These transcription factors search for binding sites, probing for the electronic patterns at the minor and major DNA groves. The eukaryotic Cys2His2 zinc finger proteins bind to DNA ubiquitously at highly conserved domains. They are responsible for gene regulation and the spatial organization of DNA. To study and understand these zinc finger DNA-protein interactions, we use the extended ladder in the DNA model proposed by Zhu, Rasmussen, Balatsky & Bishop (2007) te{Zhu-2007}. Considering one single spinless electron in each nucleotide π-orbital along a double DNA chain (dDNA), we find a typical pattern for the bottom of BOMO, HOMO and LUMO along the binding sites. We specifically looked at two members of zinc finger protein family: specificity protein 1 (SP1) and early grown response 1 transcription factors (EGR1). When the valence band is filled, we find electrons in the purines along the nucleotide sequence, compatible with the electric charges of the binding amino acids in SP1 and EGR1 zinc finger.

  19. Fingering convection induced by atomic diffusion in stars: 3D numerical computations and applications to stellar models

    SciTech Connect

    Zemskova, Varvara; Garaud, Pascale; Deal, Morgan; Vauclair, Sylvie

    2014-11-10

    Iron-rich layers are known to form in the stellar subsurface through a combination of gravitational settling and radiative levitation. Their presence, nature, and detailed structure can affect the excitation process of various stellar pulsation modes and must therefore be modeled carefully in order to better interpret Kepler asteroseismic data. In this paper, we study the interplay between atomic diffusion and fingering convection in A-type stars, as well as its role in the establishment and evolution of iron accumulation layers. To do so, we use a combination of three-dimensional idealized numerical simulations of fingering convection (which neglect radiative transfer and complex opacity effects) and one-dimensional realistic stellar models. Using the three-dimensional simulations, we first validate the mixing prescription for fingering convection recently proposed by Brown et al. (within the scope of the aforementioned approximation) and identify what system parameters (total mass of iron, iron diffusivity, thermal diffusivity, etc.) play a role in the overall evolution of the layer. We then implement the Brown et al. prescription in the Toulouse-Geneva Evolution Code to study the evolution of the iron abundance profile beneath the stellar surface. We find, as first discussed by Théado et al., that when the concurrent settling of helium is ignored, this accumulation rapidly causes an inversion in the mean molecular weight profile, which then drives fingering convection. The latter mixes iron with the surrounding material very efficiently, and the resulting iron layer is very weak. However, taking helium settling into account partially stabilizes the iron profile against fingering convection, and a large iron overabundance can accumulate. The opacity also increases significantly as a result, and in some cases it ultimately triggers dynamical convection. The direct effects of radiative acceleration on the dynamics of fingering convection (especially in the

  20. Mechanistic modeling of fingering, nonmonotonicity, fragmentation, and pulsation within gravity/buoyant destabilized two-phase/unsaturated flow

    NASA Astrophysics Data System (ADS)

    Glass, Robert J.; Yarrington, Lane

    2003-03-01

    Fingering, nonmonotonicity, fragmentation, and pulsation within gravity/buoyant destabilized two-phase/unsaturated flow systems has been widely observed with examples in homogeneous to heterogeneous porous media, in single fractures to fracture networks, and for both wetting and nonwetting invasion. To model this phenomena, we consider a mechanistic approach based on forms of modified invasion percolation (MIP) that include gravity, the influence of the local interfacial curvature along the phase-phase interface, and the simultaneous invasion and reinvasion of both wetting and nonwetting fluids. We present example simulations and compare them to experimental data for three very different situations: (1) downward gravity-driven fingering of water into a dry, homogeneous, water-wettable, porous medium; (2) upward buoyancy-driven migration of gas within a water saturated, heterogeneous, water-wettable, porous medium; and (3) downward gravity-driven fingering of water into a dry, water-wettable, rough-walled fracture.

  1. Multiple Fingers - One Gestalt.

    PubMed

    Lezkan, Alexandra; Manuel, Steven G; Colgate, J Edward; Klatzky, Roberta L; Peshkin, Michael A; Drewing, Knut

    2016-01-01

    The Gestalt theory of perception offered principles by which distributed visual sensations are combined into a structured experience ("Gestalt"). We demonstrate conditions whereby haptic sensations at two fingertips are integrated in the perception of a single object. When virtual bumps were presented simultaneously to the right hand's thumb and index finger during lateral arm movements, participants reported perceiving a single bump. A discrimination task measured the bump's perceived location and perceptual reliability (assessed by differential thresholds) for four finger configurations, which varied in their adherence to the Gestalt principles of proximity (small versus large finger separation) and synchrony (virtual spring to link movements of the two fingers versus no spring). According to models of integration, reliability should increase with the degree to which multi-finger cues integrate into a unified percept. Differential thresholds were smaller in the virtual-spring condition (synchrony) than when fingers were unlinked. Additionally, in the condition with reduced synchrony, greater proximity led to lower differential thresholds. Thus, with greater adherence to Gestalt principles, thresholds approached values predicted for optimal integration. We conclude that the Gestalt principles of synchrony and proximity apply to haptic perception of surface properties and that these principles can interact to promote multi-finger integration.

  2. Changes in thermoregulatory behavior during microwave irradiation

    SciTech Connect

    Adair, E.R.

    1981-10-01

    Voluntary behavioral action is an organism's first defense against exogenous thermal challenge. Endotherms and ectotherms alike use behavioral strategies whenever possible to counteract inhospitable alterations in the exchange of thermal energy between their bodies and the environment. Responses as diverse as the thermotropisms of unicellular organisms and the complex behavior-plus-technology of man's lunar walk share a common purpose--that of providing a hospitable microclimate so that the internal body temperature may be regulated with precision at a characteristic (neutral) level. For ectothermic species, these behaviors represent most of the thermoregulatory response available to the organism. For endothermic species, these behaviors represent most of the thermoregulatory response available to the organism. For endothermic species, these behaviors ensure minimal involvement of innate mechanisms of heat production and heat loss during thermoregulation, thus conserving the body's energy stores and water.

  3. Trigger finger

    MedlinePlus

    ... Redness in your cut or hand Swelling or warmth in your cut or hand Yellow or green drainage from the cut Hand pain or discomfort Fever If your trigger finger returns, call your surgeon. You may need another surgery.

  4. Continuous and simultaneous estimation of finger kinematics using inputs from an EMG-to-muscle activation model.

    PubMed

    Ngeo, Jimson G; Tamei, Tomoya; Shibata, Tomohiro

    2014-08-14

    Surface electromyography (EMG) signals are often used in many robot and rehabilitation applications because these reflect motor intentions of users very well. However, very few studies have focused on the accurate and proportional control of the human hand using EMG signals. Many have focused on discrete gesture classification and some have encountered inherent problems such as electro-mechanical delays (EMD). Here, we present a new method for estimating simultaneous and multiple finger kinematics from multi-channel surface EMG signals. In this study, surface EMG signals from the forearm and finger kinematic data were extracted from ten able-bodied subjects while they were tasked to do individual and simultaneous multiple finger flexion and extension movements in free space. Instead of using traditional time-domain features of EMG, an EMG-to-Muscle Activation model that parameterizes EMD was used and shown to give better estimation performance. A fast feed forward artificial neural network (ANN) and a nonparametric Gaussian Process (GP) regressor were both used and evaluated to estimate complex finger kinematics, with the latter rarely used in the other related literature. The estimation accuracies, in terms of mean correlation coefficient, were 0.85 ± 0.07, 0.78 ± 0.06 and 0.73 ± 0.04 for the metacarpophalangeal (MCP), proximal interphalangeal (PIP) and the distal interphalangeal (DIP) finger joint DOFs, respectively. The mean root-mean-square error in each individual DOF ranged from 5 to 15%. We show that estimation improved using the proposed muscle activation inputs compared to other features, and that using GP regression gave better estimation results when using fewer training samples. The proposed method provides a viable means of capturing the general trend of finger movements and shows a good way of estimating finger joint kinematics using a muscle activation model that parameterizes EMD. The results from this study demonstrates a potential control

  5. Modeling of biodynamic responses distributed at the fingers and the palm of the human hand-arm system.

    PubMed

    Dong, Ren G; Dong, Jennie H; Wu, John Z; Rakheja, Subhash

    2007-01-01

    The objective of this study is to develop analytical models for simulating driving-point biodynamic responses distributed at the fingers and palm of the hand under vibration along the forearm direction (z(h)-axis). Two different clamp-like model structures are formulated to analyze the distributed responses at the fingers-handle and palm-handle interfaces, as opposed to the single driving point invariably considered in the reported models. The parameters of the proposed four- and five degrees-of-freedom models are identified through minimization of an rms error function of the model and measured responses under different hand actions, namely, fingers pull, push only, grip only, and combined push and grip. The results show that the responses predicted from both models agree reasonably well with the measured data in terms of distributed as well total impedance magnitude and phase. The variations in the identified model parameters under different hand actions are further discussed in view of the biological system behavior. The proposed models are considered to serve as useful tools for design and assessment of vibration isolation methods, and for developing a hand-arm simulator for vibration analysis of power tools.

  6. Incubation temperature modulates post-hatching thermoregulatory behavior in the Madagascar ground gecko, Paroedura pictus.

    PubMed

    Blumberg, Mark S; Lewis, Sean J; Sokoloff, Greta

    2002-09-01

    All vertebrates regulate body temperature within narrow limits, regardless of their physiological capabilities. When do these limits develop, and can they be modified by manipulations of the developmental thermal environment? We addressed these questions by incubating the eggs of the Madagascar ground gecko, Paroedura pictus, at three temperatures and by assessing thermoregulatory behavior in hatchlings. Thermoregulatory behavior was assessed using a two-choice shuttle paradigm, and skin temperatures were measured non-invasively using infrared thermography. The shuttling behavior of hatchlings was systematically affected by the temperature at which they were incubated, and follow-up tests suggested that this effect persisted for at least three weeks post-hatching. The body temperature data from the shuttling experiment were used to model thermoregulatory behavior in a complex thermal environment; the model predicted systematic effects of incubation temperature on thermal preference. The specificity of the alteration in thermoregulatory behavior by incubation temperature is compelling and provides evidence for powerful pre-hatching influences on a fundamental, life-sustaining behavioral process.

  7. Frequency weighting for vibration-induced white finger compatible with exposure-response models.

    PubMed

    Brammer, Anthony J; Pitts, Paul M

    2012-01-01

    An analysis has been performed to derive a frequency weighting for the development of vibration-induced white finger (VWF). It employs a model to compare health risks for pairs of population groups that are selected to have similar health outcomes from operating power tools or machines with markedly different acceleration spectra (rock drills, chain saws, pavement breakers and motorcycles). The model defines the Relative Risk, RR(f(trial)), which is constructed from the ratio of daily exposures and includes a trial frequency weighting that is applied to the acceleration spectra. The trial frequency weighting consists of a frequency-independent primary frequency range, and subordinate frequency ranges in which the response to vibration diminishes, with cut-off frequencies that are changed to influence the magnitude of RR(f(trial)). The frequency weighting so derived when RR(f(trial)) = 1 is similar to those obtained by other methods (W(hf), W(hT)). It consists of a frequency independent range from about 25 Hz to 500 Hz (-3 dB frequencies), with an amplitude cut-off rate of 12 dB/octave below 25 Hz and above 500 Hz. The range is compatible with studies of vasoconstriction in persons with VWF. The results provide further evidence that the ISO frequency weighting may be inappropriate for assessing the risk of developing VWF.

  8. Decoding of individual finger movements from surface EMG signals using vector autoregressive hierarchical hidden Markov models (VARHHMM).

    PubMed

    Malesevic, Nebojsa; Markovic, Dimitrije; Kanitz, Gunter; Controzzi, Marco; Cipriani, Christian; Antfolk, Christian

    2017-07-01

    In this paper we present a novel method for predicting individual fingers movements from surface electromyography (EMG). The method is intended for real-time dexterous control of a multifunctional prosthetic hand device. The EMG data was recorded using 16 single-ended channels positioned on the forearm of healthy participants. Synchronously with the EMG recording, the subjects performed consecutive finger movements based on the visual cues. Our algorithm could be described in following steps: extracting mean average value (MAV) of the EMG to be used as the feature for classification, piece-wise linear modeling of EMG feature dynamics, implementation of hierarchical hidden Markov models (HHMM) to capture transitions between linear models, and implementation of Bayesian inference as the classifier. The performance of our classifier was evaluated against commonly used real-time classifiers. The results show that the current algorithm setup classifies EMG data similarly to the best among tested classifiers but with equal or less computational complexity.

  9. Thermoregulatory responses to environmental toxicants: The interaction of thermal stress and toxicant exposure

    SciTech Connect

    Leon, Lisa R.

    2008-11-15

    Thermal stress can have a profound impact on the physiological responses that are elicited following environmental toxicant exposure. The efficacy by which toxicants enter the body is directly influenced by thermoregulatory effector responses that are evoked in response to high ambient temperatures. In mammals, the thermoregulatory response to heat stress consists of an increase in skin blood flow and moistening of the skin surface to dissipate core heat to the environment. These physiological responses may exacerbate chemical toxicity due to increased permeability of the skin, which facilitates the cutaneous absorption of many environmental toxicants. The core temperature responses that are elicited in response to high ambient temperatures, toxicant exposure or both can also have a profound impact on the ability of an organism to survive the insult. In small rodents, the thermoregulatory response to thermal stress and many environmental toxicants (such as organophosphate compounds) is often biphasic in nature, consisting initially of a regulated reduction in core temperature (i.e., hypothermia) followed by fever. Hypothermia is an important thermoregulatory survival strategy that is used by small rodents to diminish the effect of severe environmental insults on tissue homeostasis. The protective effect of hypothermia is realized by its effects on chemical toxicity as molecular and cellular processes, such as lipid peroxidation and the formation of reactive oxygen species, are minimized at reduced core temperatures. The beneficial effects of fever are unknown under these conditions. Perspective is provided on the applicability of data obtained in rodent models to the human condition.

  10. Thermoregulatory responses to environmental toxicants: the interaction of thermal stress and toxicant exposure.

    PubMed

    Leon, Lisa R

    2008-11-15

    Thermal stress can have a profound impact on the physiological responses that are elicited following environmental toxicant exposure. The efficacy by which toxicants enter the body is directly influenced by thermoregulatory effector responses that are evoked in response to high ambient temperatures. In mammals, the thermoregulatory response to heat stress consists of an increase in skin blood flow and moistening of the skin surface to dissipate core heat to the environment. These physiological responses may exacerbate chemical toxicity due to increased permeability of the skin, which facilitates the cutaneous absorption of many environmental toxicants. The core temperature responses that are elicited in response to high ambient temperatures, toxicant exposure or both can also have a profound impact on the ability of an organism to survive the insult. In small rodents, the thermoregulatory response to thermal stress and many environmental toxicants (such as organophosphate compounds) is often biphasic in nature, consisting initially of a regulated reduction in core temperature (i.e., hypothermia) followed by fever. Hypothermia is an important thermoregulatory survival strategy that is used by small rodents to diminish the effect of severe environmental insults on tissue homeostasis. The protective effect of hypothermia is realized by its effects on chemical toxicity as molecular and cellular processes, such as lipid peroxidation and the formation of reactive oxygen species, are minimized at reduced core temperatures. The beneficial effects of fever are unknown under these conditions. Perspective is provided on the applicability of data obtained in rodent models to the human condition.

  11. Computer Applications in Thermoregulatory Research.

    ERIC Educational Resources Information Center

    DeMeersman, R. E.; Schneider, Frederick C.

    1984-01-01

    Describes a program which uses a series of algebraic equations calculating mean skin temperature and mean body temperature. The program, which uses the well-established physiological model by Burton, is written in Microsoft BASIC for TRS-80 microcomputers; however, it can be easily modified for other microcomputers. (JN)

  12. Computer Applications in Thermoregulatory Research.

    ERIC Educational Resources Information Center

    DeMeersman, R. E.; Schneider, Frederick C.

    1984-01-01

    Describes a program which uses a series of algebraic equations calculating mean skin temperature and mean body temperature. The program, which uses the well-established physiological model by Burton, is written in Microsoft BASIC for TRS-80 microcomputers; however, it can be easily modified for other microcomputers. (JN)

  13. Finger Foods for Babies

    MedlinePlus

    ... Kids to Be Smart About Social Media Finger Foods for Babies KidsHealth > For Parents > Finger Foods for ... will accept a new food. previous continue Finger Foods to Avoid Finger feeding is fun and rewarding ...

  14. Homoclinic finger-rings in RN

    NASA Astrophysics Data System (ADS)

    Zhu, Changrong; Zhang, Weinian

    2017-09-01

    In this paper we investigate bifurcations of a degenerate homoclinic loop in RN. We prove that a homoclinic finger-ring, an invariant manifold of a definite dimension textured with homoclinic orbits, arises from the degenerate homoclinic orbit. The size of the homoclinic finger-ring is decided by not only its dimension of manifold but also its width. For the rise of homoclinic finger-rings of different dimensions we give conditions, which are proved to form bifurcation manifolds in the parameter space. We further estimate the width for the homoclinic finger-ring and give a method to compute the bifurcation manifolds approximately.

  15. Modeling dynamic high-DOF finger postures from surface EMG using nonlinear synergies in latent space representation.

    PubMed

    Ngeo, Jimson; Tamei, Tomoya; Ikeda, Kazushi; Shibata, Tomohiro

    2015-01-01

    Accurate proportional myoelectric control of the hand is important in replicating dexterous manipulation in robot prostheses and orthoses. However, this is still difficult to achieve due to the complex and high degree-of-freedom (DOF) nature present in the governing musculoskeletal system. To address this problem, we suggest using a low dimensional encoding based on nonlinear synergies to represent both the high-DOF finger joint kinematics and the coordination of muscle activities taken from surface electromyographic (EMG) signals. Generating smooth multi-finger movements using EMG inputs is then done by using a shared Gaussian Process latent variable model that learns a dynamical model between both the kinematic and EMG data represented in a shared latent space. The experimental results show that the method is able to synthesize continuous movements of a full five-finger hand model, with total dimensions as large as 69 (although highly redundant and correlated). Finally, by comparing the estimation performances when the number of EMG latent dimensions are varied, we show that these synergistic features can capture the variance, shared and specific to the observed kinematics.

  16. Finger Vein Segmentation from Infrared Images Based on a Modified Separable Mumford Shah Model and Local Entropy Thresholding.

    PubMed

    Vlachos, Marios; Dermatas, Evangelos

    2015-01-01

    A novel method for finger vein pattern extraction from infrared images is presented. This method involves four steps: preprocessing which performs local normalization of the image intensity, image enhancement, image segmentation, and finally postprocessing for image cleaning. In the image enhancement step, an image which will be both smooth and similar to the original is sought. The enhanced image is obtained by minimizing the objective function of a modified separable Mumford Shah Model. Since, this minimization procedure is computationally intensive for large images, a local application of the Mumford Shah Model in small window neighborhoods is proposed. The finger veins are located in concave nonsmooth regions and, so, in order to distinct them from the other tissue parts, all the differences between the smooth neighborhoods, obtained by the local application of the model, and the corresponding windows of the original image are added. After that, veins in the enhanced image have been sufficiently emphasized. Thus, after image enhancement, an accurate segmentation can be obtained readily by a local entropy thresholding method. Finally, the resulted binary image may suffer from some misclassifications and, so, a postprocessing step is performed in order to extract a robust finger vein pattern.

  17. Autonomic thermoregulatory dysfunction in neurofibromatosis type 1.

    PubMed

    Madeira, Luciana G; Passos, Renata Lf; Souza, Juliana F de; Rezende, Nilton A; Rodrigues, Luiz O C

    2016-10-01

    Neurofibromatosis type 1 (NF1) causes neural and cutaneous disorders and reduced exercise capacity. Exercise/heat exposure increasing internal temperature must be compensated by eccrine sweat function and warmed skin vasodilation. We suspected NF1 could adversely affect eccrine sweat function and/or vascular thermoregulatory responses (VTR). The eccrine sweat function and VTR of 25 NF1 volunteers (14 males, 11 females; 16-57 years old) were compared with 23 non-NF1 controls matched by sex, age, height and weight (CG). Sweating was induced by 1) pilocarpine 1% iontophoresis (PILO); and 2) by passive heating (HEAT) via the lower third of the legs being immersed in 42°C water for one hour. Previously established eccrine sweat function and VTR protocols were used. The NF1 group showed: a) lower sweat rate than the CG group during PILO; b) a smaller diastolic pressure decrease; and c) higher tympanic temperatures than controls during HEAT (p < 0.05). Reduced sweating and vascular thermoregulatory responses suggest autonomic dysfunction in NF1 individuals.

  18. Cardiovascular response to thermoregulatory challenges

    PubMed Central

    Liu, Cuiqing; Yavar, Zubin

    2015-01-01

    A growing number of extreme climate events are occurring in the setting of ongoing climate change, with an increase in both the intensity and frequency. It has been shown that ambient temperature challenges have a direct and highly varied impact on cardiovascular health. With a rapidly growing amount of literature on this issue, we aim to review the recent publications regarding the impact of cold and heat on human populations with regard to cardiovascular disease (CVD) mortality/morbidity while also examining lag effects, vulnerable subgroups, and relevant mechanisms. Although the relative risk of morbidity/mortality associated with extreme temperature varied greatly across different studies, both cold and hot temperatures were associated with a positive mean excess of cardiovascular deaths or hospital admissions. Cause-specific study of CVD morbidity/mortality indicated that the sensitivity to temperature was disease-specific, with different patterns for acute and chronic ischemic heart disease. Vulnerability to temperature-related mortality was associated with some characteristics of the populations, including sex, age, location, socioeconomic condition, and comorbidities such as cardiac diseases, kidney diseases, diabetes, and hypertension. Temperature-induced damage is thought to be related to enhanced sympathetic reactivity followed by activation of the sympathetic nervous system, renin-angiotensin system, as well as dehydration and a systemic inflammatory response. Future research should focus on multidisciplinary adaptation strategies that incorporate epidemiology, climatology, indoor/building environments, energy usage, labor legislative perfection, and human thermal comfort models. Studies on the underlying mechanism by which temperature challenge induces pathophysiological response and CVD await profound and lasting investigation. PMID:26432837

  19. Cardiovascular response to thermoregulatory challenges.

    PubMed

    Liu, Cuiqing; Yavar, Zubin; Sun, Qinghua

    2015-12-01

    A growing number of extreme climate events are occurring in the setting of ongoing climate change, with an increase in both the intensity and frequency. It has been shown that ambient temperature challenges have a direct and highly varied impact on cardiovascular health. With a rapidly growing amount of literature on this issue, we aim to review the recent publications regarding the impact of cold and heat on human populations with regard to cardiovascular disease (CVD) mortality/morbidity while also examining lag effects, vulnerable subgroups, and relevant mechanisms. Although the relative risk of morbidity/mortality associated with extreme temperature varied greatly across different studies, both cold and hot temperatures were associated with a positive mean excess of cardiovascular deaths or hospital admissions. Cause-specific study of CVD morbidity/mortality indicated that the sensitivity to temperature was disease-specific, with different patterns for acute and chronic ischemic heart disease. Vulnerability to temperature-related mortality was associated with some characteristics of the populations, including sex, age, location, socioeconomic condition, and comorbidities such as cardiac diseases, kidney diseases, diabetes, and hypertension. Temperature-induced damage is thought to be related to enhanced sympathetic reactivity followed by activation of the sympathetic nervous system, renin-angiotensin system, as well as dehydration and a systemic inflammatory response. Future research should focus on multidisciplinary adaptation strategies that incorporate epidemiology, climatology, indoor/building environments, energy usage, labor legislative perfection, and human thermal comfort models. Studies on the underlying mechanism by which temperature challenge induces pathophysiological response and CVD await profound and lasting investigation. Copyright © 2015 the American Physiological Society.

  20. Thermoregulatory correlates of nausea in rats and musk shrews.

    PubMed

    Ngampramuan, Sukonthar; Cerri, Matteo; Del Vecchio, Flavia; Corrigan, Joshua J; Kamphee, Amornrat; Dragic, Alexander S; Rudd, John A; Romanovsky, Andrej A; Nalivaiko, Eugene

    2014-03-30

    Nausea is a prominent symptom and major cause of complaint for patients receiving anticancer chemo- or radiation therapy. The arsenal of anti-nausea drugs is limited, and their efficacy is questionable. Currently, the development of new compounds with anti-nausea activity is hampered by the lack of physiological correlates of nausea. Physiological correlates are needed because common laboratory rodents lack the vomiting reflex. Furthermore, nausea does not always lead to vomiting. Here, we report the results of studies conducted in four research centers to investigate whether nausea is associated with any specific thermoregulatory symptoms. Two species were studied: the laboratory rat, which has no vomiting reflex, and the house musk shrew (Suncus murinus), which does have a vomiting reflex. In rats, motion sickness was induced by rotating them in their individual cages in the horizontal plane (0.75 Hz, 40 min) and confirmed by reduced food consumption at the onset of dark (active) phase. In 100% of rats tested at three centers, post-rotational sickness was associated with marked (~1.5°C) hypothermia, which was associated with a short-lasting tail-skin vasodilation (skin temperature increased by ~4°C). Pretreatment with ondansetron, a serotonin 5-HT3 receptor antagonist, which is used to treat nausea in patients in chemo- or radiation therapy, attenuated hypothermia by ~30%. In shrews, motion sickness was induced by a cyclical back-and-forth motion (4 cm, 1 Hz, 15 min) and confirmed by the presence of retching and vomiting. In this model, sickness was also accompanied by marked hypothermia (~2°C). Like in rats, the hypothermic response was preceded by transient tail-skin vasodilation. In conclusion, motion sickness is accompanied by hypothermia that involves both autonomic and thermoeffector mechanisms: tail-skin vasodilation and possibly reduction of the interscapular brown adipose tissue activity. These thermoregulatory symptoms may serve as physiological

  1. Computational modeling of temperature elevation and thermoregulatory response in the brains of anesthetized rats locally exposed at 1.5 GHz

    NASA Astrophysics Data System (ADS)

    Hirata, Akimasa; Masuda, Hiroshi; Kanai, Yuya; Asai, Ryuichi; Fujiwara, Osamu; Arima, Takuji; Kawai, Hiroki; Watanabe, Soichi; Lagroye, Isabelle; Veyret, Bernard

    2011-12-01

    The dominant effect of human exposures to microwaves is caused by temperature elevation ('thermal effect'). In the safety guidelines/standards, the specific absorption rate averaged over a specific volume is used as a metric for human protection from localized exposure. Further investigation on the use of this metric is required, especially in terms of thermophysiology. The World Health Organization (2006 RF research agenda) has given high priority to research into the extent and consequences of microwave-induced temperature elevation in children. In this study, an electromagnetic-thermal computational code was developed to model electromagnetic power absorption and resulting temperature elevation leading to changes in active blood flow in response to localized 1.457 GHz exposure in rat heads. Both juvenile (4 week old) and young adult (8 week old) rats were considered. The computational code was validated against measurements for 4 and 8 week old rats. Our computational results suggest that the blood flow rate depends on both brain and core temperature elevations. No significant difference was observed between thermophysiological responses in 4 and 8 week old rats under these exposure conditions. The computational model developed herein is thus applicable to set exposure conditions for rats in laboratory investigations, as well as in planning treatment protocols in the thermal therapy.

  2. A study of the thermoregulatory characteristics of a liquid-cooled garment with automatic temperature control based on sweat rate: Experimental investigation and biothermal man-model development

    NASA Technical Reports Server (NTRS)

    Chambers, A. B.; Blackaby, J. R.; Miles, J. B.

    1973-01-01

    Experimental results for three subjects walking on a treadmill at exercise rates of up to 590 watts showed that thermal comfort could be maintained in a liquid cooled garment by using an automatic temperature controller based on sweat rate. The addition of head- and neck-cooling to an Apollo type liquid cooled garment increased its effectiveness and resulted in greater subjective comfort. The biothermal model of man developed in the second portion of the study utilized heat rates and exchange coefficients based on the experimental data, and included the cooling provisions of a liquid-cooled garment with automatic temperature control based on sweat rate. Simulation results were good approximations of the experimental results.

  3. Identification of off-target cleavage sites of zinc finger nucleases and TAL effector nucleases using predictive models.

    PubMed

    Fine, Eli J; Cradick, Thomas J; Bao, Gang

    2014-01-01

    Using engineered nucleases, such as Zinc Finger Nucleases (ZFNs) or Transcription Activator-Like Effector Nucleases (TALENs), to make targeted genomic modifications has become a common technique to create new model organisms and custom cell lines, and has shown great promise for disease treatment. However, these nucleases have the potential for off-target cleavage that could confound interpretation of experimental results and be detrimental for therapeutic use. Here, we describe a method to test for nuclease cleavage at potential off-target sites predicted by bioinformatics models.

  4. Analysis of the effects of surface stiffness on the contact interaction between a finger and a cylindrical handle using a three-dimensional hybrid model.

    PubMed

    Wu, John Z; Dong, Ren G; Warren, Christopher M; Welcome, Daniel E; McDowell, Thomas W

    2014-07-01

    Contact interactions between the hand and handle, such as the contact surface softness and contact surface curvature, will affect both physical effort and musculoskeletal fatigue, thereby the comfort and safety of power tool operations. Previous models of hand gripping can be categorized into two groups: multi-body dynamic models and finite element (FE) models. The goal of the current study is to develop a hybrid FE hand gripping model, which combines the features of conventional FE models and multi-body dynamic models. The proposed model is applied to simulate hand-gripping on a cylindrical handle with covering materials of different softness levels. The model included three finger segments (distal, middle, and proximal phalanxes), three finger joints (the distal interphalangeal (DIP), proximal interphalangeal (PIP), and metacarpophalangeal (MCP) joint), and major anatomical substructures. The model was driven by joint moments, which are the net effects of all passive and active muscular forces acting about the joints. The finger model was first calibrated by using experimental data of human subject tests, and then applied to investigate the effects of surface softness on contact interactions between a finger and a cylindrical handle. Our results show that the maximal compressive stress and strain in the soft tissues of the fingers can be effectively reduced by reducing the stiffness of the covering material.

  5. Robotic hand and fingers

    DOEpatents

    Salisbury, Curt Michael; Dullea, Kevin J.

    2017-06-06

    Technologies pertaining to a robotic hand are described herein. The robotic hand includes one or more fingers releasably attached to a robotic hand frame. The fingers can abduct and adduct as well as flex and tense. The fingers are releasably attached to the frame by magnets that allow for the fingers to detach from the frame when excess force is applied to the fingers.

  6. Competition between anisotropic viscous fingers

    NASA Astrophysics Data System (ADS)

    Pecelerowicz, M.; Budek, A.; Szymczak, P.

    2014-09-01

    We consider viscous fingers created by injection of low viscosity fluid into the network of capillaries initially filled with a more viscous fluid (motor oil). Due to the anisotropy of the system and its geometry, such a setup promotes the formation of long-and-thin fingers which then grow and compete for the available flow, interacting through the pressure field. The interaction between the fingers is analyzed using the branched growth formalism of Halsey and Leibig (Phys. Rev. A 46, 7723, 1992) using a number of simple, analytically tractable models. It is shown that as soon as the fingers are allowed to capture the flow from one another, the fixed point appears in the phase space, corresponding to the asymptotic state in which the growth of one of the fingers in hindered by the other. The properties of phase space flows in such systems are shown to be remarkably insensitive to the details of the dynamics.

  7. A thermoregulatory center in hornets: IR photography.

    PubMed

    Plotkin, Marian; Ermakov, Natalya Y; Volynchik, Stanislav; Barkay, Zahava; Bergman, David J; Ishay, Jacob S

    2005-12-15

    In the Oriental hornet Vespa orientalis (Hymenoptera, Vespinae), there is on the dorsal side of the thorax, beneath the mesoscutum plate of the prothorax and around the median notal suture, a lump that, in the course of hornet activity, is warmer by 9 degrees C from the surrounding milieu and by up to 6 degrees C from other body parts of the hornet. This lump is about 1 mm in diameter, butterfly-shaped, and its upper, posterior border abuts the base of the forewings. During hornet activity and via Infra Red photography one can observe heat extensions stemming from the center of the lump and proceeding forward in the direction of the head, downward toward the legs and backwards toward the bases of the wings. The warmest region is the center of the lump, with its margins showing a lower temperature. As for the legs of the hornet, their upper part is warmer than the other parts. The temperature gradients along the hornet's body are dependent on the extent and nature of hornet activity. Thus, during flight or ventilation activity, the thorax is the warmest part of the body, while the wings, legs, and antennae, as well as the posterior part of the gaster are colder, yet all these body parts are still warmer to varying degrees than the surrounding milieu. Thus, at night, when sentry worker hornets stand guard around the nest entrance and remain practically motionless, the temperature differences between the various body parts are retained unchanged. We conjecture that the described butterfly-shaped lump is a thermoregulatory center (TC), which is neurogenically activated, since the changes occurring in it are rapid, a matter of one to several seconds and do not appear to be directly dependent on the hemolymph supply. The thermoregulatory center keeps a high constant temperature apparently related to hornet activity and the environmental conditions. The temperature cascade is most probably regulated via the tracheal system. Apparently another system activated by a heat

  8. The independent roles of temperature and thermal perception in the control of human thermoregulatory behavior.

    PubMed

    Schlader, Zachary J; Simmons, Shona E; Stannard, Stephen R; Mündel, Toby

    2011-05-03

    The present study independently evaluated temperature and thermal perception as controllers of thermoregulatory behavior in humans. This was accomplished using a self-paced exercise and heat stress model in which twelve physically active male subjects exercised at a constant subjective rating of perceived exertion (16, 'hard--very hard') while their face was thermally and non-thermally cooled, heated, or left alone (control trial). Thermal cooling and heating were achieved via forced convection, while non-thermal cooling and heating were accomplished via the topical application of menthol and capsaicin solutions. Evidence for thermoregulatory behavior was defined in terms of self-selected exercise intensity, and thus exercise work output. The results indicate that, in the absence of changes in temperature, non-thermal cooling and warming elicited thermal sensory and discomfort sensations similar to those observed during thermal cooling and warming. Furthermore, the perception of effort was maintained throughout exercise in all trials, while the initial and final exercise intensities were also similar. Thermal and non-thermal cooling resulted in the highest work output, while thermal warming the lowest. Non-thermal warming and control trials were similar. Heart rate, mean skin and core (rectal) temperatures, and whole body and local (neck) sweat rates were similar between all trials. These data indicate that changes in temperature are not a requirement for the initiation of thermoregulatory behavior in humans. Rather, thermal sensation and thermal discomfort are capable behavioral controllers.

  9. Modeling of the biodynamic responses distributed at the fingers and palm of the hand in three orthogonal directions.

    PubMed

    Dong, Ren G; Welcome, Daniel E; McDowell, Thomas W; Wu, John Z

    2013-02-01

    The objectives of this study were to develop models of the hand-arm system in the three orthogonal directions (xh, yh , and zh ) and to enhance the understanding of the hand vibration dynamics. A four-degrees-of-freedom (DOF) model and 5-DOF model were used in the simulation for each direction. The driving-point mechanical impedances distributed at the fingers and palm of the hand reported in a previous study were used to determine the parameters of the models. The 5-DOF models were generally superior to the 4-DOF models for the simulation. Hence, as examples of applications, the 5-DOF models were used to predict the transmissibility of a vibration-reducing glove and the vibration transmissibility on the major substructures of the hand-arm system. The model-predicted results were also compared with the experimental data reported in two other recent studies. Some reasonable agreements were observed in the comparisons, which provided some validation of the developed models. This study concluded that the 5-DOF models are acceptable for helping to design and analyze vibrating tools and anti-vibration devices. This study also confirmed that the 5-DOF model in the zh direction is acceptable for a coarse estimation of the biodynamic responses distributed throughout the major substructures of the hand-arm system. Some interesting phenomena observed in the experimental study of the biodynamic responses in the three directions were also explained in this study.

  10. Modeling of the biodynamic responses distributed at the fingers and palm of the hand in three orthogonal directions

    PubMed Central

    Dong, Ren G.; Welcome, Daniel E.; McDowell, Thomas W.; Wu, John Z.

    2015-01-01

    The objectives of this study were to develop models of the hand–arm system in the three orthogonal directions (xh, yh, and zh) and to enhance the understanding of the hand vibration dynamics. A four-degrees-of-freedom (DOF) model and 5-DOF model were used in the simulation for each direction. The driving-point mechanical impedances distributed at the fingers and palm of the hand reported in a previous study were used to determine the parameters of the models. The 5-DOF models were generally superior to the 4-DOF models for the simulation. Hence, as examples of applications, the 5-DOF models were used to predict the transmissibility of a vibration-reducing glove and the vibration transmissibility on the major substructures of the hand-arm system. The model-predicted results were also compared with the experimental data reported in two other recent studies. Some reasonable agreements were observed in the comparisons, which provided some validation of the developed models. This study concluded that the 5-DOF models are acceptable for helping to design and analyze vibrating tools and anti-vibration devices. This study also confirmed that the 5-DOF model in the zh direction is acceptable for a coarse estimation of the biodynamic responses distributed throughout the major substructures of the hand–arm system. Some interesting phenomena observed in the experimental study of the biodynamic responses in the three directions were also explained in this study. PMID:26609187

  11. Modeling of the biodynamic responses distributed at the fingers and palm of the hand in three orthogonal directions

    NASA Astrophysics Data System (ADS)

    Dong, Ren G.; Welcome, Daniel E.; McDowell, Thomas W.; Wu, John Z.

    2013-02-01

    The objectives of this study were to develop models of the hand-arm system in the three orthogonal directions (xh, yh, and zh) and to enhance the understanding of the hand vibration dynamics. A four-degrees-of-freedom (DOF) model and 5-DOF model were used in the simulation for each direction. The driving-point mechanical impedances distributed at the fingers and palm of the hand reported in a previous study were used to determine the parameters of the models. The 5-DOF models were generally superior to the 4-DOF models for the simulation. Hence, as examples of applications, the 5-DOF models were used to predict the transmissibility of a vibration-reducing glove and the vibration transmissibility on the major substructures of the hand-arm system. The model-predicted results were also compared with the experimental data reported in two other recent studies. Some reasonable agreements were observed in the comparisons, which provided some validation of the developed models. This study concluded that the 5-DOF models are acceptable for helping to design and analyze vibrating tools and anti-vibration devices. This study also confirmed that the 5-DOF model in the zh direction is acceptable for a coarse estimation of the biodynamic responses distributed throughout the major substructures of the hand-arm system. Some interesting phenomena observed in the experimental study of the biodynamic responses in the three directions were also explained in this study.

  12. THE EFFECTS OF CHRONIC EXERCISE CONDITIONING ON THERMOREGULATORY RESPONSE TO CHLORPYRIFOS IN FEMALE RATS.

    EPA Science Inventory

    Chronic exercise conditioning has been shown to alter basal thermoregulatory processes (change in thermoregulatory set-point) as well as the response to infectious fever. Chlorpyrifos (CHP), an organophosphate pesticide, causes an acute period of hypothermia followed by a delaye...

  13. THE EFFECTS OF CHRONIC EXERCISE CONDITIONING ON THERMOREGULATORY RESPONSE TO CHLORPYRIFOS IN FEMALE RATS.

    EPA Science Inventory

    Chronic exercise conditioning has been shown to alter basal thermoregulatory processes (change in thermoregulatory set-point) as well as the response to infectious fever. Chlorpyrifos (CHP), an organophosphate pesticide, causes an acute period of hypothermia followed by a delaye...

  14. Body models in forensic ballistics: reconstruction of a gunshot injury to the chest by bullet fragmentation after shooting through a finger.

    PubMed

    Thali, M J; Kneubuehl, B P; Dirnhofer, R; Zollinger, U

    2001-11-15

    Forensic science uses substitutes to reconstruct injury patterns in order to answer questions regarding the dynamic formation of unusual injuries. Using a case study, an experimental simulation of a finger was designed, for the first time with a combination of hard wood and glycerin soap. With this model as an intermediate target simulation, it was possible not only to demonstrate the "bullet-body (finger) interaction", but also to recreate the wound pattern found in the victim. This case demonstrates that by using ballistic models and body-part substitutes, gunshot cases can be reproduced simply and economically, without coming into conflict with ethical guidelines.

  15. Elderly bioheat modeling: changes in physiology, thermoregulation, and blood flow circulation.

    PubMed

    Rida, Mohamad; Ghaddar, Nesreen; Ghali, Kamel; Hoballah, Jamal

    2014-11-01

    A bioheat model for the elderly was developed focusing on blood flow circulatory changes that influence their thermal response in warm and cold environments to predict skin and core temperatures for different segments of the body especially the fingers. The young adult model of Karaki et al. (Int J Therm Sci 67:41-51, 2013) was modified by incorporation of the physiological thermoregulatory and vasomotor changes based on literature observations of physiological changes in the elderly compared to young adults such as lower metabolism and vasoconstriction diminished ability, skin blood flow and its minimum and maximum values, the sweating values, skin fat thickness, as well as the change in threshold parameter related to core or skin temperatures which triggers thermoregulatory action for sweating, maximum dilatation, and maximum constriction. The developed model was validated with published experimental data for elderly exposure to transient and steady hot and cold environments. Predicted finger skin temperature, mean skin temperature, and core temperature were in agreement with published experimental data at a maximum error less than 0.5 °C in the mean skin temperature. The elderly bioheat model showed an increase in finger skin temperature and a decrease in core temperature in cold exposure while it showed a decrease in finger skin temperature and an increase in core temperature in hot exposure.

  16. A thermal manikin with human thermoregulatory control: Implementation and validation

    NASA Astrophysics Data System (ADS)

    Foda, Ehab; Sirén, Kai

    2012-09-01

    Tens of different sorts of thermal manikins are employed worldwide, mainly in the evaluation of clothing thermal insulation and thermal environments. They are regulated thermally using simplified control modes. This paper reports on the implementation and validation of a new thermoregulatory control mode for thermal manikins. The new control mode is based on a multi-segmental Pierce (MSP) model. In this study, the MSP control mode was implemented, using the LabVIEW platform, onto the control system of the thermal manikin `Therminator'. The MSP mode was then used to estimate the segmental equivalent temperature ( t eq) along with constant surface temperature (CST) mode under two asymmetric thermal conditions. Furthermore, subjective tests under the same two conditions were carried out using 17 human subjects. The estimated segmental t eq from the experiments with the two modes and from the subjective assessment were compared in order to validate the use of the MSP mode for the estimation of t eq. The results showed that the t eq values estimated by the MSP mode were closer to the subjective mean votes under the two test conditions for most body segments and compared favourably with values estimated by the CST mode.

  17. A thermal manikin with human thermoregulatory control: implementation and validation.

    PubMed

    Foda, Ehab; Sirén, Kai

    2012-09-01

    Tens of different sorts of thermal manikins are employed worldwide, mainly in the evaluation of clothing thermal insulation and thermal environments. They are regulated thermally using simplified control modes. This paper reports on the implementation and validation of a new thermoregulatory control mode for thermal manikins. The new control mode is based on a multi-segmental Pierce (MSP) model. In this study, the MSP control mode was implemented, using the LabVIEW platform, onto the control system of the thermal manikin 'Therminator'. The MSP mode was then used to estimate the segmental equivalent temperature (t(eq)) along with constant surface temperature (CST) mode under two asymmetric thermal conditions. Furthermore, subjective tests under the same two conditions were carried out using 17 human subjects. The estimated segmental t(eq) from the experiments with the two modes and from the subjective assessment were compared in order to validate the use of the MSP mode for the estimation of t(eq). The results showed that the t(eq) values estimated by the MSP mode were closer to the subjective mean votes under the two test conditions for most body segments and compared favourably with values estimated by the CST mode.

  18. Phase-field modeling of two-dimensional solute precipitation/dissolution: Solid fingers and diffusion-limited precipitation

    SciTech Connect

    Zhijie Xu; Paul Meakin

    2011-01-01

    Two-dimensional dendritic growth due to solute precipitation was simulated using a phase-field model reported earlier [Z. Xu and P. Meakin, J. Chem. Phys. 129, 014705 (2008)]. It was shown that diffusion-limited precipitation due to the chemical reaction at the solid–liquid interface has similarities with diffusion-limited aggregation (DLA). The diffusion-limited precipitation is attained by setting the chemical reaction rate much larger compared to the solute diffusion to eliminate the effect of the interface growth kinetics. The phase-field simulation results were in reasonable agreement with the analytical solutions. The fractal solid fingers can be formed in the diffusion-limited precipitation and have a fractal dimension measured df = 1.68, close to 1.64, the fractal dimensionality of large square lattice DLA clusters.

  19. Phase-field modeling of two-dimensional solute precipitation/dissolution: Solid fingers and diffusion-limited precipitation

    SciTech Connect

    Xu, Zhijie; Meakin, Paul

    2011-01-28

    Two-dimensional dendritic growth due to solute precipitation was simulated using a phase-field model reported earlier [Z. Xu and P. Meakin, J. Chem. Phys. 129, 014705 (2008)]. It was shown that diffusion-limited precipitation due to the chemical reaction at the solid-liquid interface posses similarities with diffusion-limited aggregation (DLA). The diffusion-limited precipitation is attained by setting the chemical reaction rate much larger compared to the solute diffusion to eliminate the effect of the interface growth kinetics. The phase-field simulation results were in reasonable agreement with the analytical solutions. The fractal solid fingers can be formed in the diffusion-limited precipitation and have a fractal dimension measured , close to 1.64, the fractal dimensionality of large square lattice diffusion-limited aggregation (DLA) clusters.

  20. Phase-field modeling of two-dimensional solute precipitation∕dissolution: solid fingers and diffusion-limited precipitation.

    PubMed

    Xu, Zhijie; Meakin, Paul

    2011-01-28

    Two-dimensional dendritic growth due to solute precipitation was simulated using a phase-field model reported earlier [Z. Xu and P. Meakin, J. Chem. Phys. 129, 014705 (2008)]. It was shown that diffusion-limited precipitation due to the chemical reaction at the solid-liquid interface has similarities with diffusion-limited aggregation (DLA). The diffusion-limited precipitation is attained by setting the chemical reaction rate much larger compared to the solute diffusion to eliminate the effect of the interface growth kinetics. The phase-field simulation results were in reasonable agreement with the analytical solutions. The fractal solid fingers can be formed in the diffusion-limited precipitation and have a fractal dimension measured d(f)=1.68, close to 1.64, the fractal dimensionality of large square lattice DLA clusters.

  1. An over expression APP model for anti-Alzheimer disease drug screening created by zinc finger nuclease technology.

    PubMed

    Zhang, Xiaojing; Li, Hui; Mao, Yiqing; Li, Zhixin; Wang, Rong; Guo, Tingting; Jin, Ling; Song, Rongjing; Xu, Wei; Zhou, Na; Zhang, Yizhuang; Hu, Ruobi; Wang, Xi; Huang, Huakang; Lei, Zhen; Niu, Gang; Irwin, David M; Tan, Huanran

    2013-01-01

    Zinc Finger Nucleases (ZFNs), famous for their ability to precisely and efficiently modify specific genomic loci, have been employed in numerous transgenic model organism and cell constructions. Here we employ the ZFNs technology, with homologous recombination (HR), to construct sequence-specific Amyloid Precursor Protein (APP) knock-in cells. With the use of ZFNs, we established APP knock in cell lines with gene-modification efficiencies of about 7%. We electroporated DNA fragment containing the promoter and the protein coding regions of the zinc finger nucleases into cells, instead of the plasmids, to avoid problems associated with off target homologous recombination, and adopted a pair of mutated FokI cleavage domains to reduce the toxic effects of the ZFNs on cell growth. Since over-expression of APP, or a subdomain of it, might lead to an immediately lethal effect, we used the Cre-LoxP System to regulate APP expression. Our genetically transformed cell lines, w5c1 and s12c8, showed detectable APP and Amyloid β (Aβ) production. The Swedish double mutation in the APP coding sequence enhanced APP and Aβ abundance. What is more, the activity of the three key secretases in Aβ formation could be modulated, indicating that these transgenic cells have potential for drug screening to modify amyloid metabolism in cells. Our transformed cells could readily be propagated in culture and should provide an excellent experimental medium for elucidating aspects of the molecular pathogenesis of Alzheimer's disease, especially those concerning the amyloidogenic pathways involving mutations in the APP coding sequence. The cellular models may also serve as a tool for deriving potentially useful therapeutic agents.

  2. Thermoregulatory adaptations associated with training and heat acclimation.

    PubMed

    Geor, R J; McCutcheon, L J

    1998-04-01

    The large metabolic heat load generated as a consequence of muscular work requires activation of thermoregulatory mechanisms in order to prevent an excessive and potentially dangerous rise in body temperature during exercise. Although the horse has highly efficient heat dissipatory mechanisms, there are a number of circumstances in which the thermoregulatory system may be overwhelmed, resulting in the development of critical hyperthermia. The risk for development of life-threatening hyperthermia is greatest when (1) the horse is inadequately conditioned for the required level of physical performance; (2) exercise is undertaken in hot and particularly, in hot and humid ambient conditions; and (3) there is an impairment to thermoregulatory mechanisms (e.g., severe dehydration, anhidrosis). Both exercise training under cool to moderate ambient conditions and a period of repeated exposure to, and exercise in, hot ambient conditions (heat acclimation) will result in a number of physiologic adaptations conferring improved thermoregulatory ability. These adaptations include an expanded plasma volume, greater stability of cardiovascular function during exercise, and an improved efficiency of evaporative heat loss as a result of alterations in the sweating response. Collectively, these adjustments serve to attenuate the rise in core body temperature in response to a given intensity of exercise. The magnitude of the physiologic adaptations occurring during exercise training and heat acclimation is a reflection of the thermal load imposed on the horse. Therefore, when compared with a period of training in cool conditions, the larger thermal stimulus associated with repeated exercise in hot ambient conditions will invoke proportionally greater thermoregulatory adaptations. Although it is not possible to eliminate the effects of adverse environmental conditions on exercise performance, it is clear that a thorough exercise training program together with a subsequent period of

  3. Nicotine effects on thermoregulatory responses of men and women during acute cold exposure.

    PubMed

    Cheatham, Christopher C; Caine-Bish, Natalie; Blegen, Mark; Potkanowicz, Edward S; Glickman, Ellen L

    2004-07-01

    Due to the impact of nicotine (NIC) on the physiological processes involved in temperature regulation during cold exposure, it is conceivable that NIC may affect the body's thermoregulatory abilities during a cold stress. Thus, the purpose of this study was to examine the effects of NIC on thermoregulatory responses during acute cold exposure. There were six men and six women between the ages of 18 and 25 yr who participated in this study. All subjects were active, apparently healthy smokers. Each subject performed two cold air trials consisting of a 30-min baseline period (BASE) and a 120-min exposure to 10 degrees C air. One cold air trial was performed following a NIC dosing using a 21-mg transdermal patch while the other trial was performed after a placebo (PL) treatment. During the cold air trials, there were no differences in rectal temperature (Tre) or mean skin temperature (Tsk) between the PL and NIC treatments in either sex (p > 0.05). However, in men, heat production (M) was 12% lower (p < or = 0.05) and tissue insulation was 17% higher (p < or = 0.05) during the NIC treatment compared with the PL treatment, while these responses in women were unaffected. In both men and women, finger skin vascular conductance (SVCfin), expressed as a percentage of the BASE value, was higher during the NIC treatment compared with the PL treatment during the cold air trials (p < or = 0.05). Lastly, throughout the cold air trials, there was no difference in thermal sensation between the PL and NIC treatments (p > 0.05). In conclusion, although NIC administration resulted in sex-specific alterations in M and tissue insulation during cold exposure, the response in Tre was unaffected.

  4. Current concepts: mallet finger.

    PubMed

    Alla, Sreenivasa R; Deal, Nicole D; Dempsey, Ian J

    2014-06-01

    Loss of the extensor mechanism at the distal interphalangeal (DIP) joint leads to mallet finger also known as baseball finger or drop finger. This can be secondary to tendon substance disruption or to a bony avulsion. Soft tissue mallet finger is the result of a rupture of the extensor tendon in Zone 1, and a bony mallet finger is the result of an avulsion of the extensor tendon from the distal phalanx with a small fragment of bone attached to the avulsed tendon. Mallet finger leads to an imbalance in the distribution of the extensor force between the proximal interphalangeal (PIP) and DIP joints. If left untreated, mallet finger leads to a swan neck deformity from PIP joint hyper extension and DIP joint flexion. Most mallet finger injuries can be managed non-surgically, but occasionally surgery is recommended for either an acute or a chronic mallet finger or for salvage of failed prior treatment.

  5. Scattering Removal for Finger-Vein Image Restoration

    PubMed Central

    Yang, Jinfeng; Zhang, Ben; Shi, Yihua

    2012-01-01

    Finger-vein recognition has received increased attention recently. However, the finger-vein images are always captured in poor quality. This certainly makes finger-vein feature representation unreliable, and further impairs the accuracy of finger-vein recognition. In this paper, we first give an analysis of the intrinsic factors causing finger-vein image degradation, and then propose a simple but effective image restoration method based on scattering removal. To give a proper description of finger-vein image degradation, a biological optical model (BOM) specific to finger-vein imaging is proposed according to the principle of light propagation in biological tissues. Based on BOM, the light scattering component is sensibly estimated and properly removed for finger-vein image restoration. Finally, experimental results demonstrate that the proposed method is powerful in enhancing the finger-vein image contrast and in improving the finger-vein image matching accuracy. PMID:22737028

  6. Scattering removal for finger-vein image restoration.

    PubMed

    Yang, Jinfeng; Zhang, Ben; Shi, Yihua

    2012-01-01

    Finger-vein recognition has received increased attention recently. However, the finger-vein images are always captured in poor quality. This certainly makes finger-vein feature representation unreliable, and further impairs the accuracy of finger-vein recognition. In this paper, we first give an analysis of the intrinsic factors causing finger-vein image degradation, and then propose a simple but effective image restoration method based on scattering removal. To give a proper description of finger-vein image degradation, a biological optical model (BOM) specific to finger-vein imaging is proposed according to the principle of light propagation in biological tissues. Based on BOM, the light scattering component is sensibly estimated and properly removed for finger-vein image restoration. Finally, experimental results demonstrate that the proposed method is powerful in enhancing the finger-vein image contrast and in improving the finger-vein image matching accuracy.

  7. THE VELOCITY OF DNAPL FINGERING IN WATER-SATURATED POROUS MEDIA LABORATORY EXPERIMENTS AND A MOBILE-IMMOBILE-ZONE MODEL. (R826157)

    EPA Science Inventory

    Dense nonaqueous phase liquids (DNAPLs) are immiscible with water and can give rise to highly fingered fluid distributions when infiltrating through water-saturated porous media. In this paper, a conceptual mobile¯immobile¯zone (MIZ) model is pr...

  8. THE VELOCITY OF DNAPL FINGERING IN WATER-SATURATED POROUS MEDIA LABORATORY EXPERIMENTS AND A MOBILE-IMMOBILE-ZONE MODEL. (R826157)

    EPA Science Inventory

    Dense nonaqueous phase liquids (DNAPLs) are immiscible with water and can give rise to highly fingered fluid distributions when infiltrating through water-saturated porous media. In this paper, a conceptual mobile¯immobile¯zone (MIZ) model is pr...

  9. Female anthropometric variability and their effects on predicted thermoregulatory responses to work in the heat

    NASA Astrophysics Data System (ADS)

    Yokota, Miyo; Berglund, Larry G.; Bathalon, Gaston P.

    2012-03-01

    The use of thermoregulatory models for assessing physiological responses of workers in thermally stressful situations has been increasing because of the risks and costs related to human studies. In a previous study (Yokota et al. Eur J Appl Physiol 104:297-302, 2008), the effects of anthropometric variability on predicted physiological responses to heat stress in U.S. Army male soldiers were evaluated. Five somatotypes were identified in U.S. Army male multivariate anthropometric distribution. The simulated heat responses, using a thermoregulatory model, were different between somatotypes. The present study further extends this line of research to female soldiers. Anthropometric somatotypes were identified using multivariate analysis [height, weight, percent body fat (%BF)] and the predicted physiological responses to simulated exercise and heat stress using a thermoregulatory model were evaluated. The simulated conditions included walking at ~3 mph (4.8 km/h) for 300 min and wearing battle dress uniform and body armor in a 30°C, 25% relative humidity (RH) environment without solar radiation. Five major somatotypes (tall-fat, tall-lean, average, short-lean, and short-fat), identified through multivariate analysis of anthropometric distributions, showed different tolerance levels to simulated heat stress: lean women were predicted to maintain their core temperatures (Tc) lower than short-fat or tall-fat women. The measured Tc of female subjects obtained from two heat studies (data1: 30°C, 32% RH, protective garments, ~225 w·m-2 walk for 90 min; data2: 32°C, 75% RH, hot weather battle dress uniform, ~378 ± 32 w·m-2 for 30 min walk/30 min rest cycles for 120 min) were utilized for validation. Validation results agreed with the findings in this study: fat subjects tended to have higher core temperatures than medium individuals (data2) and lean subjects maintained lower core temperatures than medium subjects (data1).

  10. Female anthropometric variability and their effects on predicted thermoregulatory responses to work in the heat.

    PubMed

    Yokota, Miyo; Berglund, Larry G; Bathalon, Gaston P

    2012-03-01

    The use of thermoregulatory models for assessing physiological responses of workers in thermally stressful situations has been increasing because of the risks and costs related to human studies. In a previous study (Yokota et al. Eur J Appl Physiol 104:297-302, 2008), the effects of anthropometric variability on predicted physiological responses to heat stress in U.S. Army male soldiers were evaluated. Five somatotypes were identified in U.S. Army male multivariate anthropometric distribution. The simulated heat responses, using a thermoregulatory model, were different between somatotypes. The present study further extends this line of research to female soldiers. Anthropometric somatotypes were identified using multivariate analysis [height, weight, percent body fat (%BF)] and the predicted physiological responses to simulated exercise and heat stress using a thermoregulatory model were evaluated. The simulated conditions included walking at ~3 mph (4.8 km/h) for 300 min and wearing battle dress uniform and body armor in a 30°C, 25% relative humidity (RH) environment without solar radiation. Five major somatotypes (tall-fat, tall-lean, average, short-lean, and short-fat), identified through multivariate analysis of anthropometric distributions, showed different tolerance levels to simulated heat stress: lean women were predicted to maintain their core temperatures (T(c)) lower than short-fat or tall-fat women. The measured T(c) of female subjects obtained from two heat studies (data1: 30°C, 32% RH, protective garments, ~225 w·m(-2) walk for 90 min; data2: 32°C, 75% RH, hot weather battle dress uniform, ~378 ± 32 w·m(-2) for 30 min walk/30 min rest cycles for 120 min) were utilized for validation. Validation results agreed with the findings in this study: fat subjects tended to have higher core temperatures than medium individuals (data2) and lean subjects maintained lower core temperatures than medium subjects (data1).

  11. Integration of Sensory Information via Central Thermoregulatory Leptin Targets

    PubMed Central

    Rezai-Zadeh, Kavon; Münzberg, Heike

    2013-01-01

    The adipocyte derived hormone leptin acts in the brain to regulate body weight, food intake and energy expenditure. Even though it is well accepted that leptin regulates energy expenditure at least in part by modulating thermogenesis, the exact mechanisms are not clear. Particularly, it is unclear which central circuits regulate thermogenic leptin actions and if and how these may interact with feeding circuits. Within the last decade our understanding of central thermoregulatory circuits has increased substantially and allowed the identification of leptin target neurons (those expressing the long form leptin receptor –LepRb) that are involved in the sympathetic control of the heat generating brown adipose tissue (BAT). Indeed, LepRb neurons in the preoptic area and dorsomedial hypothalamus are part of known thermoregulatory circuits controlling sympathetic premotor neurons that are located in the raphe pallidus. Thermoregulatory control and food intake are both regulated by leptin signaling pathways, even though distinct neuronal pathways have been described, respectively. Nevertheless, feeding status and control of body temperature and energy expenditure are tightly interconnected, but it is unknown how these aspects are connected within leptin signaling pathways to result in appropriate output signals (e.g. BAT thermogenesis). Indeed, cold-induced thermogenesis is potently blocked during fasting, which instead triggers an active decrease in energy expenditure and body temperature, a state known as torpor. In this article we will review recent data characterizing central thermoregulatory LepRb pathways and speculate on potential integration mechanisms that may relay anorexic and thermoregulatory leptin action to control energy homeostasis. PMID:23458626

  12. Thermoregulatory disorders and illness related to heat and cold stress.

    PubMed

    Cheshire, William P

    2016-04-01

    Thermoregulation is a vital function of the autonomic nervous system in response to cold and heat stress. Thermoregulatory physiology sustains health by keeping body core temperature within a degree or two of 37°C, which enables normal cellular function. Heat production and dissipation are dependent on a coordinated set of autonomic responses. The clinical detection of thermoregulatory impairment provides important diagnostic and localizing information in the evaluation of disorders that impair thermoregulatory pathways, including autonomic neuropathies and ganglionopathies. Failure of neural thermoregulatory mechanisms or exposure to extreme or sustained temperatures that overwhelm the body's thermoregulatory capacity can also result in potentially life-threatening departures from normothermia. Hypothermia, defined as a core temperature of <35.0°C, may present with shivering, respiratory depression, cardiac dysrhythmias, impaired mental function, mydriasis, hypotension, and muscle dysfunction, which can progress to cardiac arrest or coma. Management includes warming measures, hydration, and cardiovascular support. Deaths from hypothermia are twice as frequent as deaths from hyperthermia. Hyperthermia, defined as a core temperature of >40.5°C, may present with sweating, flushing, tachycardia, fatigue, lightheadedness, headache, and paresthesia, progressing to weakness, muscle cramps, oliguria, nausea, agitation, hypotension, syncope, confusion, delirium, seizures, and coma. Mental status changes and core temperature distinguish potentially fatal heat stroke from heat exhaustion. Management requires the immediate reduction of core temperature. Ice water immersion has been shown to be superior to alternative cooling measures. Avoidance of thermal risk and early recognition of cold or heat stress are the cornerstones of preventive therapy. Copyright © 2016 The Author. Published by Elsevier B.V. All rights reserved.

  13. Differing Dynamics of Intrapersonal and Interpersonal Coordination: Two-finger and Four-Finger Tapping Experiments

    PubMed Central

    Kodama, Kentaro; Furuyama, Nobuhiro; Inamura, Tetsunari

    2015-01-01

    Finger-tapping experiments were conducted to examine whether the dynamics of intrapersonal and interpersonal coordination systems can be described equally by the Haken—Kelso—Bunz model, which describes inter-limb coordination dynamics. This article reports the results of finger-tapping experiments conducted in both systems. Two within-subject factors were investigated: the phase mode and the number of fingers. In the intrapersonal experiment (Experiment 1), the participants were asked to tap, paced by a gradually hastening auditory metronome, looking at their fingers moving, using the index finger in the two finger condition, or the index and middle finger in the four-finger condition. In the interpersonal experiment (Experiment 2), pairs of participants performed the task while each participant used the outside hand, tapping with the index finger in the two finger condition, or the index and middle finger in the four-finger condition. Some results did not agree with the HKB model predictions. First, from Experiment 1, no significant difference was observed in the movement stability between the in-phase and anti-phase modes in the two finger condition. Second, from Experiment 2, no significant difference was found in the movement stability between the in-phase and anti-phase mode in the four-finger condition. From these findings, different coordination dynamics were inferred between intrapersonal and interpersonal coordination systems against prediction from the previous studies. Results were discussed according to differences between intrapersonal and interpersonal coordination systems in the availability of perceptual information and the complexity in the interaction between limbs derived from a nested structure. PMID:26070119

  14. A 3D thermal model to analyze the temperature changes of digits during cold stress and predict the danger of frostbite in human fingers.

    PubMed

    Fallahi, Amir; Reza Salimpour, Mohammad; Shirani, Ebrahim

    2017-04-01

    The existing computational models of frostbite injury are limited to one and two dimensional schemes. In this study, a coupled thermo-fluid model is applied to simulate a finger exposed to cold weather. The spatial variability of finger-tip temperature is compared to experimental ones to validate the model. A semi-realistic 3D model for tissue and blood vessels is used to analyze the transient heat transfer through the finger. The effect of heat conduction, metabolic heat generation, heat transport by blood perfusion, heat exchange between tissues and large vessels are considered in energy balance equations. The current model was then tested in different temperatures and air speeds to predict the danger of frostbite in humans for different gloves. Two prevalent gloves which are commonly used in cold climate are considered for investigation. The endurance time and the fraction of necrotic tissues are two main factors suggested for obtaining the response of digit tissues to different environmental conditions. Copyright © 2017 Elsevier Ltd. All rights reserved.

  15. Behavioral, Ventilatory and Thermoregulatory Responses to Hypercapnia and Hypoxia in the Wistar Audiogenic Rat (WAR) Strain

    PubMed Central

    Giusti, Humberto; Oliveira, José Antonio; Glass, Mogens Lesner; Garcia-Cairasco, Norberto

    2016-01-01

    Introduction We investigated the behavioral, respiratory, and thermoregulatory responses elicited by acute exposure to both hypercapnic and hypoxic environments in Wistar audiogenic rats (WARs). The WAR strain represents a genetic animal model of epilepsy. Methods Behavioral analyses were performed using neuroethological methods, and flowcharts were constructed to illustrate behavioral findings. The body plethysmography method was used to obtain pulmonary ventilation (VE) measurements, and body temperature (Tb) measurements were taken via temperature sensors implanted in the abdominal cavities of the animals. Results No significant difference was observed between the WAR and Wistar control group with respect to the thermoregulatory response elicited by exposure to both acute hypercapnia and acute hypoxia (p>0.05). However, we found that the VE of WARs was attenuated relative to that of Wistar control animals during exposure to both hypercapnic (WAR: 133 ± 11% vs. Wistar: 243 ± 23%, p<0.01) and hypoxic conditions (WAR: 138 ± 8% vs. Wistar: 177 ± 8%; p<0.01). In addition, we noted that this ventilatory attenuation was followed by alterations in the behavioral responses of these animals. Conclusions Our results indicate that WARs, a genetic model of epilepsy, have important alterations in their ability to compensate for changes in levels of various arterial blood gasses. WARs present an attenuated ventilatory response to an increased PaCO2 or decreased PaO2, coupled to behavioral changes, which make them a suitable model to further study respiratory risks associated to epilepsy. PMID:27149672

  16. Laplacian trees - fingered growth in channel geometry

    NASA Astrophysics Data System (ADS)

    Szymczak, P.; Gubiec, T.

    2009-04-01

    A variety of natural growth processes, including viscous fingering, electrodeposition, or solidification can be modeled in terms of Laplacian growth. Laplacian growth patterns are formed when the boundary of a domain moves with a velocity proportional to the gradient of a field Ψ, which satisfies the Laplace equation, ‡2Ψ = 0, outside the domain. A simple model of Laplacian growth is considered, in which the growth takes place only at the tips of long, thin fingers [1]. The evolution of the fingers is studied by conformal mapping techniques. Analytical and numerical solutions are obtained for different domains and boundary conditions. In particular, a screening process is analyzed, when longer fingers suppress growth of the shorter ones. Possible geophysical applications of the model are discussed, including formation and evolution of the channels in a dissolving rock fracture. [1] T. Gubiec, P. Szymczak, Fingered growth in channel geometry: A Loewner equation approach , Phys. Rev. E, 77 , 041602, 2008

  17. Let your fingers do the walking: A simple spectral signature model for "remote" fossil prospecting.

    PubMed

    Conroy, Glenn C; Emerson, Charles W; Anemone, Robert L; Townsend, K E Beth

    2012-07-01

    Even with the most meticulous planning, and utilizing the most experienced fossil-hunters, fossil prospecting in remote and/or extensive areas can be time-consuming, expensive, logistically challenging, and often hit or miss. While nothing can predict or guarantee with 100% assurance that fossils will be found in any particular location, any procedures or techniques that might increase the odds of success would be a major benefit to the field. Here we describe, and test, one such technique that we feel has great potential for increasing the probability of finding fossiliferous sediments - a relatively simple spectral signature model using the spatial analysis and image classification functions of ArcGIS(®)10 that creates interactive thematic land cover maps that can be used for "remote" fossil prospecting. Our test case is the extensive Eocene sediments of the Uinta Basin, Utah - a fossil prospecting area encompassing ∼1200 square kilometers. Using Landsat 7 ETM+ satellite imagery, we "trained" the spatial analysis and image classification algorithms using the spectral signatures of known fossil localities discovered in the Uinta Basin prior to 2005 and then created interactive probability models highlighting other regions in the Basin having a high probability of containing fossiliferous sediments based on their spectral signatures. A fortuitous "post-hoc" validation of our model presented itself. Our model identified several paleontological "hotspots", regions that, while not producing any fossil localities prior to 2005, had high probabilities of being fossiliferous based on the similarities of their spectral signatures to those of previously known fossil localities. Subsequent fieldwork found fossils in all the regions predicted by the model. Copyright © 2012 Elsevier Ltd. All rights reserved.

  18. Basal Forebrain Thermoregulatory Mechanism Modulates Auto-Regulated Sleep

    PubMed Central

    Mallick, Hruda Nanda; Kumar, Velayudhan Mohan

    2012-01-01

    Regulation of body temperature and sleep are two physiological mechanisms that are vital for our survival. Interestingly neural structures implicated in both these functions are common. These areas include the medial preoptic area (POA), the lateral POA, the ventrolateral POA, the median preoptic nucleus, and the medial septum, which form part of the basal forebrain (BF). When given a choice, rats prefer to stay at an ambient temperature of 27°C, though the maximum sleep was observed when they were placed at 30°C. Ambient temperature around 27°C should be considered as the thermoneutral temperature for rats in all sleep studies. At this temperature the diurnal oscillations of sleep and body temperature are properly expressed. The warm sensitive neurons of the POA mediate the increase in sleep at 30°C. Promotion of sleep during the rise in ambient temperature from 27 to 30°C, serve a thermoregulatory function. Autonomous thermoregulatory changes in core body temperature and skin temperature could act as an input signal to modulate neuronal activity in sleep-promoting brain areas. The studies presented here show that the neurons of the BF play a key role in regulating sleep. BF thermoregulatory system is a part of the global homeostatic sleep regulatory mechanism, which is auto-regulated. PMID:22754548

  19. Generation of SNCA Cell Models Using Zinc Finger Nuclease (ZFN) Technology for Efficient High-Throughput Drug Screening.

    PubMed

    Dansithong, Warunee; Paul, Sharan; Scoles, Daniel R; Pulst, Stefan M; Huynh, Duong P

    2015-01-01

    Parkinson's disease (PD) is a progressive neurodegenerative disorder caused by loss of dopaminergic neurons of the substantia nigra. The hallmark of PD is the appearance of neuronal protein aggregations known as Lewy bodies and Lewy neurites, of which α-synuclein forms a major component. Familial PD is rare and is associated with missense mutations of the SNCA gene or increases in gene copy number resulting in SNCA overexpression. This suggests that lowering SNCA expression could be therapeutic for PD. Supporting this hypothesis, SNCA reduction was neuroprotective in cell line and rodent PD models. We developed novel cell lines expressing SNCA fused to the reporter genes luciferase (luc) or GFP with the objective to enable high-throughput compound screening (HTS) for small molecules that can lower SNCA expression. Because SNCA expression is likely regulated by far-upstream elements (including the NACP-REP1 located at 8852 bp upstream of the transcription site), we employed zinc finger nuclease (ZFN) genome editing to insert reporter genes in-frame downstream of the SNCA gene in order to retain native SNCA expression control. This ensured full retention of known and unknown up- and downstream genetic elements controlling SNCA expression. Treatment of cells with the histone deacetylase inhibitor valproic acid (VPA) resulted in significantly increased SNCA-luc and SNCA-GFP expression supporting the use of our cell lines for identifying small molecules altering complex modes of expression control. Cells expressing SNCA-luc treated with a luciferase inhibitor or SNCA siRNA resulted in Z'-scores ≥ 0.75, suggesting the suitability of these cell lines for use in HTS. This study presents a novel use of genome editing for the creation of cell lines expressing α-synuclein fusion constructs entirely under native expression control. These cell lines are well suited for HTS for compounds that lower SNCA expression directly or by acting at long-range sites to the SNCA

  20. Highly Unstable Double-Diffusive Finger Convection in a Hele-Shaw Cell: Baseline Experimental Data for Evaluation of Numerical Models

    SciTech Connect

    PRINGLE,SCOTT E.; COOPER,CLAY A.; GLASS JR.,ROBERT J.

    2000-12-21

    An experimental investigation was conducted to study double-diffusive finger convection in a Hele-Shaw cell by layering a sucrose solution over a more-dense sodium chloride (NaCl) solution. The solutal Rayleigh numbers were on the order of 60,000, based upon the height of the cell (25 cm), and the buoyancy ratio was 1.2. A full-field light transmission technique was used to measure a dye tracer dissolved in the NaCl solution. They analyze the concentration fields to yield the temporal evolution of length scales associated with the vertical and horizontal finger structure as well as the mass flux. These measures show a rapid progression through two early stages to a mature stage and finally a rundown period where mass flux decays rapidly. The data are useful for the development and evaluation of numerical simulators designed to model diffusion and convection of multiple components in porous media. The results are useful for correct formulation at both the process scale (the scale of the experiment) and effective scale (where the lab-scale processes are averaged-up to produce averaged parameters). A fundamental understanding of the fine-scale dynamics of double-diffusive finger convection is necessary in order to successfully parameterize large-scale systems.

  1. Trajectory of the index finger during grasping.

    PubMed

    Friedman, Jason; Flash, Tamar

    2009-07-01

    The trajectory of the index finger during grasping movements was compared to the trajectories predicted by three optimization-based models. The three models consisted of minimizing the integral of the weighted squared joint derivatives along the path (inertia-like cost), minimizing torque change, and minimizing angular jerk. Of the three models, it was observed that the path of the fingertip and the joint trajectories, were best described by the minimum angular jerk model. This model, which does not take into account the dynamics of the finger, performed equally well when the inertia of the finger was altered by adding a 20 g weight to the medial phalange. Thus, for the finger, it appears that trajectories are planned based primarily on kinematic considerations at a joint level.

  2. More efficient swimming by spreading your fingers

    NASA Astrophysics Data System (ADS)

    van de Water, Willem; van Houwelingen, Josje; Willemsen, Dennis; Breugem, Wim Paul; Westerweel, Jerry; Delfos, Rene; Grift, Ernst Jan

    2016-11-01

    A tantalizing question in free-style swimming is whether the stroke efficiency during the pull phase depends on spreading the fingers. It is a subtle effect-not more than a few percent-but it could make a big difference in a race. We measure the drag of arm models with increasing finger spreading in a wind tunnel and compare forces and moments to the results of immersed boundary simulations. Virtual arms were used in the simulations and their 3D-printed real versions in the experiment. We find an optimal finger spreading, accompanied by a marked increase of coherent vortex shedding. A simple actuator disk model explains this optimum.

  3. Rolling friction robot fingers

    NASA Technical Reports Server (NTRS)

    Vranish, John M. (Inventor)

    1992-01-01

    A low friction, object guidance, and gripping finger device for a robotic end effector on a robotic arm is disclosed, having a pair of robotic fingers each having a finger shaft slideably located on a gripper housing attached to the end effector. Each of the robotic fingers has a roller housing attached to the finger shaft. The roller housing has a ball bearing mounted centering roller located at the center, and a pair of ball bearing mounted clamping rollers located on either side of the centering roller. The object has a recess to engage the centering roller and a number of seating ramps for engaging the clamping rollers. The centering roller acts to position and hold the object symmetrically about the centering roller with respect to the X axis and the clamping rollers act to position and hold the object with respect to the Y and Z axis.

  4. Individual variability in finger-to-finger transmission efficiency of Enterococcus faecium clones

    PubMed Central

    del Campo, Rosa; Sánchez-Díaz, Ana María; Zamora, Javier; Torres, Carmen; Cintas, Luis María; Franco, Elvira; Cantón, Rafael; Baquero, Fernando

    2014-01-01

    A fingertip-to-fingertip intraindividual transmission experiment was carried out in 30 healthy volunteers, using four MLST-typed Enterococcus faecium clones. Overall results showed an adequate fit goodness to a theoretical exponential model, whereas four volunteers (13%) exhibited a significantly higher finger-to-finger bacterial transmission efficiency. This observation might have deep consequences in nosocomial epidemiology. PMID:24382843

  5. Thermoregulatory consequences of salt loading in the lizard Pogona vitticeps.

    PubMed

    Scarpellini, Carolina da Silveira; Bícego, Kênia C; Tattersall, Glenn J

    2015-04-15

    Previous research has demonstrated that dehydration increases the threshold temperature for panting and decreases the thermal preference of lizards. Conversely, it is unknown whether thermoregulatory responses such as shuttling and gaping are similarly influenced. Shuttling, as an active behavioural response, is considered one of the most effective thermoregulatory behaviours, whereas gaping has been proposed to be involved in preventing brain over-heating in lizards. In this study we examined the effect of salt loading, a proxy for increased plasma osmolality, on shuttling and gaping in Pogona vitticeps. Then, we determined the upper and lower escape ambient temperatures (UETa and LETa), the percentage of time spent gaping, the metabolic rate (V̇O2 ), the evaporative water loss (EWL) during gaping and non-gaping intervals and the evaporative effectiveness (EWL/V̇O2 ) of gaping. All experiments were performed under isotonic (154 mmol l(-1)) and hypertonic saline injections (625, 1250 or 2500 mmol l(-1)). Only the highest concentration of hypertonic saline altered the UETa and LETa, but this effect appeared to be the result of diminishing the animal's propensity to move, instead of any direct reduction in thermoregulatory set-points. Nevertheless, the percentage of time spent gaping was proportionally reduced according to the saline concentration; V̇O2 was also decreased after salt loading. Thermographic images revealed lower head than body surface temperatures during gaping; however this difference was inhibited after salt loading. Our data suggest that EWL/V̇O2 is raised during gaping, possibly contributing to an increase in heat transfer away from the lizard, and playing a role in head or brain cooling.

  6. A Unique Facility For Metabolic and Thermoregulatory Studies

    NASA Technical Reports Server (NTRS)

    Williamson, Rebecca C.; Webbon, Bruce W.

    1995-01-01

    A unique exercise facility has been developed and used to perform tipper body ergometry tests for space applications. Originally designed to simulate the muscular, cardiovascular and thermoregulatory responses to working in zero gravity, this facility may be used to conduct basic thermoregulatory investigations applicable to multiple sclerosis patients. An environmental chamber houses the tipper body ergometer and permits control of temperature, air now and humidify. The chamber is a closed system and recirculate-s air after conditioning if. A Cybex Lipper body ergometer has been mounted horizontally on the wall of the environmental chamber. In this configuration, the subject lies underneath the arm crank on a supine seat in order to turn the crank. The supine seat can be removed in order to introduce other equipment into the chamber such as a stool to allow upright arm cranking, or a treadmill to allow walk-run experiments. Physiological and environmental signals are fed into a Strawberry Tree data acquisition system while being monitored and logged using the Workbench software program. Physiological monitoring capabilities include 3-lead EKG using an H-P patient monitor, 5 site skin temperature and core temperature using YSI thermistors, and O2 consumption and CO2 production using AMFTFK Applied Electrochemistry analyzers and sensors. This comprehensive data acquisition set tip allows for calculation of various thermoregulatory indices including heat storage, evaporative heat loss, latent heat loss, and metabolic rate. The current system is capable of adding more data acquisition channels if needed. Some potential studies that could be carried out using the facility include: 1) An investigation into the efficiency of cooling various segments of the body to lower Tc 1-2 F. 2) A series of heat and mass balance studies comparing various LCG configurations.

  7. Generation of SNCA Cell Models Using Zinc Finger Nuclease (ZFN) Technology for Efficient High-Throughput Drug Screening

    PubMed Central

    Dansithong, Warunee; Paul, Sharan; Scoles, Daniel R.; Pulst, Stefan M.; Huynh, Duong P.

    2015-01-01

    Parkinson’s disease (PD) is a progressive neurodegenerative disorder caused by loss of dopaminergic neurons of the substantia nigra. The hallmark of PD is the appearance of neuronal protein aggregations known as Lewy bodies and Lewy neurites, of which α-synuclein forms a major component. Familial PD is rare and is associated with missense mutations of the SNCA gene or increases in gene copy number resulting in SNCA overexpression. This suggests that lowering SNCA expression could be therapeutic for PD. Supporting this hypothesis, SNCA reduction was neuroprotective in cell line and rodent PD models. We developed novel cell lines expressing SNCA fused to the reporter genes luciferase (luc) or GFP with the objective to enable high-throughput compound screening (HTS) for small molecules that can lower SNCA expression. Because SNCA expression is likely regulated by far-upstream elements (including the NACP-REP1 located at 8852 bp upstream of the transcription site), we employed zinc finger nuclease (ZFN) genome editing to insert reporter genes in-frame downstream of the SNCA gene in order to retain native SNCA expression control. This ensured full retention of known and unknown up- and downstream genetic elements controlling SNCA expression. Treatment of cells with the histone deacetylase inhibitor valproic acid (VPA) resulted in significantly increased SNCA-luc and SNCA-GFP expression supporting the use of our cell lines for identifying small molecules altering complex modes of expression control. Cells expressing SNCA-luc treated with a luciferase inhibitor or SNCA siRNA resulted in Z’-scores ≥ 0.75, suggesting the suitability of these cell lines for use in HTS. This study presents a novel use of genome editing for the creation of cell lines expressing α-synuclein fusion constructs entirely under native expression control. These cell lines are well suited for HTS for compounds that lower SNCA expression directly or by acting at long-range sites to the SNCA

  8. Five- to 7-year-olds' finger gnosia and calculation abilities.

    PubMed

    Reeve, Robert; Humberstone, Judi

    2011-01-01

    The research examined the relationship between 65 5- to 7-year-olds' finger gnosia, visuo-spatial working memory, and finger-use in solving single-digit addition problems. Their non-verbal IQ and basic reaction time were also assessed. Previous research has found significant changes in children's representational abilities between 5 and 7 years. One aim of the research was to determine whether changes in finger representational abilities (finger gnosia) occur across these ages and whether they are associated with finger-use in computation. A second aim was to determine whether visuo-spatial working memory is associated with finger gnosia and computation abilities. We used latent class profile analysis to identify patterns of similarities and differences in finger gnosia and computation/finger-use abilities. The analysis yielded four finger gnosia subgroups that differed in finger representation ability. It also yielded four finger/computation subgroups that differed in the relationship between finger-use and computation success. Analysis revealed associations between computation finger-use/success subgroups, finger gnosia subgroups, and visuo-spatial working memory. A multinomial logistic regression analysis showed that finger gnosia subgroup membership and visuo-spatial working memory uniquely contribute to a model predicting finger-use in computation group membership. The results show that finger gnosia abilities change in the early school years, and that these changes are associated with the ability to use fingers to aid computation.

  9. Five- to 7-Year-Olds’ Finger Gnosia and Calculation Abilities

    PubMed Central

    Reeve, Robert; Humberstone, Judi

    2011-01-01

    The research examined the relationship between 65 5- to 7-year-olds’ finger gnosia, visuo-spatial working memory, and finger-use in solving single-digit addition problems. Their non-verbal IQ and basic reaction time were also assessed. Previous research has found significant changes in children’s representational abilities between 5 and 7 years. One aim of the research was to determine whether changes in finger representational abilities (finger gnosia) occur across these ages and whether they are associated with finger-use in computation. A second aim was to determine whether visuo-spatial working memory is associated with finger gnosia and computation abilities. We used latent class profile analysis to identify patterns of similarities and differences in finger gnosia and computation/finger-use abilities. The analysis yielded four finger gnosia subgroups that differed in finger representation ability. It also yielded four finger/computation subgroups that differed in the relationship between finger-use and computation success. Analysis revealed associations between computation finger-use/success subgroups, finger gnosia subgroups, and visuo-spatial working memory. A multinomial logistic regression analysis showed that finger gnosia subgroup membership and visuo-spatial working memory uniquely contribute to a model predicting finger-use in computation group membership. The results show that finger gnosia abilities change in the early school years, and that these changes are associated with the ability to use fingers to aid computation. PMID:22171220

  10. Thermoregulatory responses to heat and vibration in men

    NASA Technical Reports Server (NTRS)

    Spaul, W. A.; Spear, R. C.; Greenleaf, J. E.

    1986-01-01

    The effect of vibration on thermoregulatory responses was studied in heat-acclimated men exposed suddenly to simultaneous heat and whole body vibrations (WBVs) at two intensity levels, each at graded frequencies between 5 and 80 Hz. The mean rectal temperature (Tre) became elevated more quickly in the WBV exposures than in the controls (heat exposure alone). Both intensity- and frequency-dependent WBV relationships were recorded in localized blood flows and in sweat rates. Thus, vibration appears to reduce the efficiency of the cooling mechanisms during a heat exposure.

  11. Osseointegrated finger prostheses.

    PubMed

    Doppen, P; Solomons, M; Kritzinger, S

    2009-02-01

    Amputation of a digit can lead to functional and psychological problems and patients can benefit from digital prostheses. Unfortunately, standard prostheses are often unstable, particularly when fitted over short amputation stumps. Prosthesis fixation by osseointegration is widely used in oral and extraoral applications and may help avoid the problem of instability. This paper reports the results of four patients with five finger amputations who were treated with osseointegrated implants to attach finger prostheses. One implant failed to osseointegrate and the procedure was abandoned. Three patients were successfully treated to completion of three finger prostheses and are extremely satisfied with their outcomes, both cosmetically and functionally, with osseoperception reported by all three patients.

  12. Finger Cooling During Cold Air Exposure.

    NASA Astrophysics Data System (ADS)

    Tikuisis, Peter

    2004-05-01

    This paper presents a method for predicting the onset of finger freezing. It is an extension of a tissue-cooling model originally developed to predict the onset of cheek freezing. The extension to the finger is presented as a more conservative warning of wind chill. Indeed, guidance on the risk of finger freezing is important not only to safeguard the finger, but also because it pertains more closely to susceptible facial features, such as the nose, than if only the risk of cheek freezing was provided. The importance of blood flow to the finger and the modeling of vaso-constriction are demonstrated through cooling predictions that agree reasonably well with several reported observations. Differences in the prediction between the present physiologic-based model and the engineering model used to develop the wind chill index are also discussed. New wind chill charts are presented that tabulate the mean cooling rates and corresponding onset times to freezing of the finger for various combinations of air temperature and wind speed. Results indicate that the surface of the finger cools to its freezing point in approximately one-eighth of the time predicted for the cheek. For combinations that result in the same wind chill temperature (WCT), the rate of finger cooling is faster at the higher wind speed. This asymmetry was previously disclosed through the application of the model to cheek cooling, and it reiterates the ambiguity associated with the reporting of WCT. It is further emphasized that the reporting of onset times to freezing, or safe exposure limits, is a more logical and meaningful alternative to the WCT.

  13. Finger Foods for Babies

    MedlinePlus

    ... textures. No longer are baby purees and mushy cereals the only things on the menu. By the ... ll still be helping out by spoon-feeding cereal and other important dietary elements. Encouraging finger feeding ...

  14. Nickel transfer by fingers.

    PubMed

    Isnardo, D; Vidal, J; Panyella, D; Vilaplana, J

    2015-06-01

    We investigated fingers as a potential source of nickel transfer to the face in patients with allergic contact dermatitis to nickel and a history of facial dermatitis. Samples were collected from the fingers and cheeks of volunteers using the stripping method with standard adhesive tape, and nickel levels were quantified using mass spectrometry. Fingers and cheeks of individuals who had handled coins were both positive for nickel, with levels ranging from 14.67 to 58.64 ppm and 1.28 to 8.52 ppm, respectively. The levels in a control group were considerably and significantly lower. Transfer of nickel from a person's fingers to their face after handling a nickel-containing object could explain the presence of facial dermatitis in patients with nickel hypersensitivity.

  15. Hand and Finger Exercises

    MedlinePlus

    ... each fingertip. Repeat ____ times for ____ seconds.  Bend the end joint of your finger, keeping the base and middle joints straight. Hold this position. Relax and then straighten the end joint. Hold this position. Repeat ____ times for ____ seconds.  ...

  16. Do female newts modify thermoregulatory behavior to manipulate egg size?

    PubMed

    Toufarová, Eliška; Gvoždík, Lumír

    2016-04-01

    Reproductive females manipulate offspring phenotypes by modifying conditions during embryogenesis. In ectotherms, the environmental control over embryogenesis is often realized by changes in maternal thermoregulation during gravidity. To determine if reproduction influences thermoregulatory behavior in species where females lay eggs shortly after fertilization (strict oviparity), we compared preferred body temperatures (Tp) between reproductive (egg-laying) and non-reproductive female newts, Ichthyosaura alpestris. Next, we exposed reproductive females to temperatures mimicking Tp ranges of reproductive and non-reproductive individuals to find out whether the maternally modified thermal regime influences ovum and jelly coat volume, and early cleavage rates at the time of oviposition. In the thermal gradient, reproductive females maintained their body temperatures within a narrower range than non-reproductive individuals. The exposure of ovipositing females to temperatures preferred during their reproductive and non-reproductive period had a negligible influence on egg size and early cleavage rates. We conclude that the modification of maternal thermoregulatory behavior provides a limited opportunity to manipulate egg traits in newts.

  17. Effects of intracerebroventricular capsaicin on thermoregulatory behavior in the rat.

    PubMed

    Dib, B

    1982-01-01

    To clarify the action of capsaicin on the thermoregulatory system of rat, behavioral and autonomic responses were studied following intracerebroventricular (ICV) injection. Rats were chronically implanted with a lateral cerebral ventricular guide cannula. After the recovery period they were placed in a climatic chamber at ambient temperature (Ta) of 20, 30 or 35 degrees C. In the first series of experiments, they had access to a lever which activated a fan that drew cool outside air into the chamber. After ICV capsaicin (23 micrograms), the rats increased bar-pressing behavior for fresh air at Ta ranging from 20 degrees C to 35 degrees C. In the second series of experiment, the rats had no access to fanning. ICV capsaicin produced a fall in rectal and hypothalamic temperature (Thy) and an increased in cutaneous temperature. These changes depended on Ta. At a Ta of 30 degrees C Thy fell slightly (mean of 0.2 +/- 0.16 degrees C). At a Ta of 20 degrees C Thy fell to a mean of 1 degree C +/- 0.17 degrees C. The conclusion drawn is ICV capsaicin activated behavioral as well as autonomic thermoregulatory heat-loss responses. The effect of capsaicin resembles the effect of local heating of the hypothalamus. However, since hypothalamic temperature decreased the drug may have lowered the thermal set point, or excited directly hypothalamic warm-sensitive neurons.

  18. Ontogeny of thermoregulatory mechanisms in king penguin chicks (Aptenodytes patagonicus).

    PubMed

    Duchamp, Claude; Rouanet, Jean Louis; Barré, Hervé

    2002-04-01

    The rapid maturation of thermoregulatory mechanisms may be of critical importance for optimising chick growth and survival and parental energy investment under harsh climatic conditions. The ontogeny of thermoregulatory mechanisms was studied in growing king penguin chicks from hatching to the full emancipation observed at 1 month of age in the sub-Antarctic area (Crozet Archipelago). Newly hatched chicks showed small, but significant regulatory thermogenesis (21% rise in heat production assessed by indirect calorimetry), but rapidly became hypothermic. Within a few days, both resting (+32%) and peak (+52%) metabolic rates increased. The first week of life was characterised by a two-fold rise in thermogenic capacity in the cold, while thermal insulation was not improved. During the second and third weeks of age, thermal insulation markedly rose (two-fold drop in thermal conductance) in relation to down growth, while resting heat production was slightly reduced (-13%). Shivering (assessed by electromyography) was visible right after hatching, although its efficiency was limited. Thermogenic efficiency of shivering increased five-fold with age during the first weeks of life, but there was no sign of non-shivering thermogenesis. We conclude that thermal emancipation of king penguin chicks may be primarily determined by improvement of thermal insulation after thermogenic processes have become sufficiently matured. Both insulative and metabolic adaptations are required for the rapid ontogeny of thermoregulation and thermal emancipation in growing king penguin chicks.

  19. Temporal Sequencing of Brain Activations During Naturally Occurring Thermoregulatory Events

    PubMed Central

    Diwadkar, Vaibhav A.; Murphy, Eric R.; Freedman, Robert R.

    2014-01-01

    Thermoregulatory events are associated with activity in the constituents of the spinothalamic tract. Whereas studies have assessed activity within constituents of this pathway, in vivo functional magnetic resonance imaging (fMRI) studies have not determined if neuronal activity in the constituents of the tract is temporally ordered. Ordered activity would be expected in naturally occurring thermal events, such as menopausal hot flashes (HFs), which occur in physiological sequence. The origins of HFs may lie in brainstem structures where neuronal activity may occur earlier than in interoceptive centers, such as the insula and the prefrontal cortex. To study such time ordering, we conducted blood oxygen level-dependent-based fMRI in a group of postmenopausal women to measure neuronal activity in the brainstem, insula, and prefrontal cortex around the onset of an HF (detected using synchronously acquired skin conductance responses). Rise in brainstem activity occurred before the detectable onset of an HF. Activity in the insular and prefrontal trailed that in the brainstem, appearing following the onset of the HF. Additional activations associated with HF's were observed in the anterior cingulate cortex and the basal ganglia. Pre-HF brainstem responses may reflect the functional origins of internal thermoregulatory events. By comparison insular, prefrontal and striatal activity may be associated with the phenomenological correlates of HFs. PMID:23787950

  20. The thermoregulatory theory of yawning: what we know from over 5 years of research

    PubMed Central

    Gallup, Andrew C.; Eldakar, Omar T.

    2012-01-01

    Over the past 5 years numerous reports have confirmed and replicated the specific brain cooling and thermal window predictions derived from the thermoregulatory theory of yawning, and no study has found evidence contrary to these findings. Here we review the comparative research supporting this model of yawning among homeotherms, while highlighting a recent report showing how the expression of contagious yawning in humans is altered by seasonal climate variation. The fact that yawning is constrained to a thermal window of ambient temperature provides unique and compelling support in favor of this theory. Heretofore, no existing alternative hypothesis of yawning can explain these results, which have important implications for understanding the potential functional role of this behavior, both physiologically and socially, in humans and other animals. In discussion we stress the broader applications of this work in clinical settings, and counter the various criticisms of this theory. PMID:23293583

  1. Adherence to Bergmann's rule by lizards may depend on thermoregulatory mode: support from a nocturnal gecko.

    PubMed

    Penniket, Sophie; Cree, Alison

    2015-06-01

    Bergmann's rule predicts an increase in body size with decreasing environmental temperature; however, the converse pattern has been found in the majority of lizards studied to date. For these ectotherms, small body size may provide thermal benefits (rapid heat uptake when basking), which would be highly advantageous in cold environments. Yet such an advantage may not exist in nocturnal lizards (which do not avidly bask), in which Bergmann's rule has not been closely studied. We have examined whether the body size of a primarily nocturnal gecko, Woodworthia "Otago/Southland" changed with elevation and operative temperature (determined using physical copper models). In a laboratory study, we investigated whether thermoregulatory mode (heliothermy or thigmothermy) alters the effect of body size on heating and cooling rates. This gecko followed Bergmann's rule, thereby showing the opposite of the dominant pattern in diurnal lizards. Size at maturity, maximum size of adults and size at birth were larger at higher elevations and at lower operative temperatures. Using physical models, we found that large body size can confer thermal benefits for nocturnal lizards that remain within diurnal retreats. Bergmann's rule should not be dismissed for all lizards. Our results clearly support Bergmann's rule for at least one thigmothermic species, for which large body size may provide thermal benefits. Future studies on Bergmann's rule in lizards should consider thermoregulatory mode. We advocate that this ecogeographic rule be examined in relation to operative temperature measured at field sites. Finally, we predict that climate warming may weaken the relationship between body size and elevation in this gecko.

  2. Tendon Driven Finger Actuation System

    NASA Technical Reports Server (NTRS)

    Ihrke, Chris A. (Inventor); Reich, David M. (Inventor); Bridgwater, Lyndon (Inventor); Linn, Douglas Martin (Inventor); Askew, Scott R. (Inventor); Diftler, Myron A. (Inventor); Platt, Robert (Inventor); Hargrave, Brian (Inventor); Valvo, Michael C. (Inventor); Abdallah, Muhammad E. (Inventor); Permenter, Frank Noble (Inventor); Mehling, Joshua S. (Inventor)

    2013-01-01

    A humanoid robot includes a robotic hand having at least one finger. An actuation system for the robotic finger includes an actuator assembly which is supported by the robot and is spaced apart from the finger. A tendon extends from the actuator assembly to the at least one finger and ends in a tendon terminator. The actuator assembly is operable to actuate the tendon to move the tendon terminator and, thus, the finger.

  3. Finger and toenail onycholysis.

    PubMed

    Zaias, N; Escovar, S X; Zaiac, M N

    2015-05-01

    Onycholysis - the separation of the nail plate from the nail bed occurs in fingers and toenails. It is diagnosed by the whitish appearance of the separated nail plate from the nail bed. In fingers, the majority is caused by trauma, manicuring, occupational or self-induced behavior. The most common disease producing fingernail onycholysis is psoriasis and pustular psoriasis. Phototoxic dermatitis, due to drugs can also produce finger onycholysis. Once the separation occurs, the environmental flora sets up temporary colonization in the available space. Finger onycholysis is most common in women. Candida albicans is often recovered from the onycholytic space. Many reports, want to associate the yeast as cause and effect, but the data are lacking and the treatment of the candida does not improve finger onycholysis. A reasonable explanation for the frequent isolation of Candida and Pseudomonas in fingernail onycholysis in women, is the close proximity the fingers have to the vaginal and gastrointestinal tract. Fifty per cent of humans harbour C. albicans in the GI tract and it is frequently carried to the vagina during hygienic practices. Finger onycholysis is best treated by drying the nail 'lytic' area with a hair blower, since all colonizing biota are moisture loving and perish in a dry environment. Toenail onycholysis has a very different etiology. It is mechanical, the result of pressure on the toes from the closed shoes, while walking, because of the ubiquitous uneven flat feet producing an asymmetric gait with more pressure on the foot with the flatter sole. © 2014 European Academy of Dermatology and Venereology.

  4. Protein-energy malnutrition alters thermoregulatory homeostasis and the response to brain ischemia.

    PubMed

    Smith, Shari E; Prosser-Loose, Erin J; Colbourne, Frederick; Paterson, Phyllis G

    2011-02-01

    Co-existing protein-energy malnutrition (PEM), characterized by deficits in both protein and energy status, impairs functional outcome following global ischemia and has been associated with increased reactive gliosis. Since temperature is a key determinant of brain damage following an ischemic insult, the objective was to investigate whether alterations in post-ischemic temperature regulation contribute to PEM-induced reactive gliosis following ischemia. Male Sprague-Dawley rats (190-280 g) were assigned to either control diet (18% protein) or PEM induced by feeding a low protein diet (2% protein) for 7 days prior to either global ischemia or sham surgery. There was a rapid disruption in thermoregulatory function in rats fed the low protein diet as assessed by continuous recording of core temperature with bio-electrical sensor transmitters. Both daily temperature fluctuation and mean temperature increased within the first 24 hours, and these remained significantly elevated throughout the 7 day pre-ischemic period (p < 0.027). In the immediate post-surgical period, PEM decreased body temperature to a greater extent than that in well-nourished controls (p = 0.003). The increase in daily temperature fluctuation caused by PEM persisted throughout the 7 day post-surgical period (p < 0.001), and this interacted with the effects of global ischemia on days 8 (p = 0.018) and 11 (p = 0.021). The astrocytic and microglial responses induced at 7 days after global ischemia were not influenced by PEM, but this preliminary analysis needs to be confirmed with a more reliable global ischemia model. In conclusion, exposure to a low protein diet rapidly impairs the ability to maintain thermoregulatory homeostasis, and the resultant PEM also diminishes the ability to thermoregulate in response to a challenge. Since temperature regulation is a key determinant of brain injury following ischemia, these findings suggest that the pathophysiology of brain injury could be altered in stroke

  5. Swimming propulsion forces are enhanced by a small finger spread.

    PubMed

    Marinho, Daniel A; Barbosa, Tiago M; Reis, Victor M; Kjendlie, Per L; Alves, Francisco B; Vilas-Boas, João P; Machado, Leandro; Silva, António J; Rouboa, Abel I

    2010-02-01

    The main aim of this study was to investigate the effect of finger spread on the propulsive force production in swimming using computational fluid dynamics. Computer tomography scans of an Olympic swimmer hand were conducted. This procedure involved three models of the hand with differing finger spreads: fingers closed together (no spread), fingers with a small (0.32 cm) spread, and fingers with large (0.64 cm) spread. Steady-state computational fluid dynamics analyses were performed using the Fluent code. The measured forces on the hand models were decomposed into drag and lift coefficients. For hand models, angles of attack of 0 degrees, 15 degrees, 30 degrees, 45 degrees, 60 degrees, 75 degrees, and 90 degrees, with a sweep back angle of 0 degrees, were used for the calculations. The results showed that the model with a small spread between fingers presented higher values of drag coefficient than did the models with fingers closed and fingers with a large spread. One can note that the drag coefficient presented the highest values for an attack angle of 90 degrees in the three hand models. The lift coefficient resembled a sinusoidal curve across the attack angle. The values for the lift coefficient presented few differences among the three models, for a given attack angle. These results suggested that fingers slightly spread could allow the hand to create more propulsive force during swimming.

  6. Stroke volume monitored by modeling flow from finger arterial pressure waves mirrors blood volume withdrawn by phlebotomy.

    PubMed

    Leonetti, Pascal; Audat, Françoise; Girard, Arlette; Laude, Dominique; Lefrère, François; Elghozi, Jean-Luc

    2004-06-01

    Rate-controlled blood withdrawal was used to reduce cardiac preload and consequently stroke volume in patients with normal cardiac function. Twelve patients with asymptomatic hereditary hemochromatosis, undergoing regular phlebotomy therapy, volunteered for the study. An average volume of 375 ml was withdrawn in an average period of 6.4 min. Finger pressure was continuously measured by a Finometer device which includes the Beatscope software for deriving the stroke volume from the blood pressure waveform. Blood withdrawal resulted in reduction of the stroke volume estimates (from 94.0 +/- 5.2 to 80.7 +/- 5.3, P < 0.05) together with a reduced pulse pressure (from 53.0 +/- 3.5 to 47.1 +/- 3.2, P < 0.05). No significant changes in heart rate (75.2 +/- 3.7 versus 78.3 +/- 4.5 beats/min) were observed. Calculated cardiac output was reduced while calculated total peripheral resistance was elevated after blood withdrawal. Beat-to-beat analysis demonstrated a significant linear regression between most of the hemodynamic indices and the volume withdrawn. The highest correlation coefficients were found for the stroke volume (0.88 +/- 0.01, P < 0.001) and the pulse pressure (0.80 +/- 0.04, P < 0.001) corresponding also to the highest slopes for the lines relating these measures to the relative blood volume withdrawn. The non-invasive estimation of finger blood pressure can be used to derive simple on-line indices (pulse pressure, stroke volume using the Modelflow) of cardiac preload, which are of major interest in the monitoring of cardiovascular status.

  7. Transient Receptor Potential Ion Channels Control Thermoregulatory Behaviour in Reptiles

    PubMed Central

    Seebacher, Frank; Murray, Shauna A.

    2007-01-01

    Biological functions are governed by thermodynamics, and animals regulate their body temperature to optimise cellular performance and to avoid harmful extremes. The capacity to sense environmental and internal temperatures is a prerequisite for the evolution of thermoregulation. However, the mechanisms that enable ectothermic vertebrates to sense heat remain unknown. The recently discovered thermal characteristics of transient receptor potential ion channels (TRP) render these proteins suitable to act as temperature sensors. Here we test the hypothesis that TRPs are present in reptiles and function to control thermoregulatory behaviour. We show that the hot-sensing TRPV1 is expressed in a crocodile (Crocodylus porosus), an agamid (Amphibolurus muricatus) and a scincid (Pseudemoia entrecasteauxii) lizard, as well as in the quail and zebrafinch (Coturnix chinensis and Poephila guttata). The TRPV1 genes from all reptiles form a unique clade that is delineated from the mammalian and the ancestral Xenopus sequences by an insertion of two amino acids. TRPV1 and the cool-sensing TRPM8 are expressed in liver, muscle (transversospinalis complex), and heart tissues of the crocodile, and have the potential to act as internal thermometer and as external temperatures sensors. Inhibition of TRPV1 and TRPM8 in C. porosus abolishes the typically reptilian shuttling behaviour between cooling and heating environments, and leads to significantly altered body temperature patterns. Our results provide the proximate mechanism of thermal selection in terrestrial ectotherms, which heralds a fundamental change in interpretation, because TRPs provide the mechanism for a tissue-specific input into the animals' thermoregulatory response. PMID:17356692

  8. City-scale expansion of human thermoregulatory costs.

    PubMed

    Hill, Richard W; Muhich, Timothy E; Humphries, Murray M

    2013-01-01

    The physiological maintenance of a stable internal temperature by mammals and birds - the phenomenon termed homeothermy - is well known to be energetically expensive. The annual energy requirements of free-living mammals and birds are estimated to be 15-30 times higher than those of similar-size ectothermic vertebrates like lizards. Contemporary humans also use energy to accomplish thermoregulation. They are unique, however, in having shifted thermoregulatory control from the body to the occupied environment, with most people living in cities in dwellings that are temperature-regulated by furnaces and air conditioners powered by exogenous energy sources. The energetic implications of this strategy remain poorly defined. Here we comparatively quantify energy costs in cities, dwellings, and individual human bodies. Thermoregulation persists as a major driver of energy expenditure across these three scales, resulting in energy-versus-ambient-temperature relationships remarkably similar in shape. Incredibly, despite the many and diversified uses of network-delivered energy in modern societies, the energy requirements of six North American cities are as temperature-dependent as the energy requirements of isolated, individual homeotherms. However, the annual per-person energy cost of exogenously powered thermoregulation in cities and dwellings is 9-28 times higher than the cost of endogenous, metabolic thermoregulation of the human body. Shifting the locus of thermoregulatory control from the body to the dwelling achieves climate-independent thermal comfort. However, in an era of amplifying climate change driven by the carbon footprint of humanity, we must acknowledge the energetic extravagance of contemporary, city-scale thermoregulation, which prioritizes heat production over heat conservation.

  9. 3-Iodothyroacetic acid lacks thermoregulatory and cardiovascular effects in vivo

    PubMed Central

    Hoefig, Carolin S; Jacobi, Simon F; Warner, Amy; Harder, Lisbeth; Schanze, Nancy; Vennström, Björn; Mittag, Jens

    2015-01-01

    Background and Purpose 3-Iodothyronamine (3-T1AM) is an endogenous thyroid hormone derivative reported to induce strong hypothermia and bradycardia within minutes upon injection in rodents. Although 3-T1AM is rapidly converted to several other metabolites in vivo, these strong pharmacological responses were solely attributed to 3-T1AM, leaving potential contributions of downstream products untested. We therefore examined the cardiometabolic effects of 3-iodothyroacetic acid (TA1), the main degradation product of 3-T1AM. Experimental Approach We used a sensitive implantable radiotelemetry system in C57/Bl6J mice to study the effects of TA1 on body temperature and heart rate, as well as other metabolic parameters. Key Results Interestingly, despite using pharmacological TA1 doses, we observed no effects on heart rate or body temperature after a single TA1 injection (50 mg·kg−1, i.p.) compared to sham-injected controls. Repeated administration of TA1 (5 mg·kg−1, i.p. for 7 days) likewise did not alter body weight, food and water intake, heart rate, blood pressure, brown adipose tissue (BAT) thermogenesis or body temperature. Moreover, mRNA expression of tissue specific genes in heart, kidney, liver, BAT and lung was also not altered by TA1 compared to sham-injected controls. Conclusions and Implications Our data therefore conclusively demonstrate that TA1 does not contribute to the cardiovascular or thermoregulatory effects observed after 3-T1AM administration in mice, suggesting that the oxidative deamination constitutes an important deactivation mechanism for 3-T1AM with possible implications for cardiovascular and thermoregulatory functions. PMID:25765843

  10. 3-Iodothyroacetic acid lacks thermoregulatory and cardiovascular effects in vivo.

    PubMed

    Hoefig, Carolin S; Jacobi, Simon F; Warner, Amy; Harder, Lisbeth; Schanze, Nancy; Vennström, Björn; Mittag, Jens

    2015-07-01

    3-Iodothyronamine (3-T1 AM) is an endogenous thyroid hormone derivative reported to induce strong hypothermia and bradycardia within minutes upon injection in rodents. Although 3-T1 AM is rapidly converted to several other metabolites in vivo, these strong pharmacological responses were solely attributed to 3-T1 AM, leaving potential contributions of downstream products untested. We therefore examined the cardiometabolic effects of 3-iodothyroacetic acid (TA1 ), the main degradation product of 3-T1 AM. We used a sensitive implantable radiotelemetry system in C57/Bl6J mice to study the effects of TA1 on body temperature and heart rate, as well as other metabolic parameters. Interestingly, despite using pharmacological TA1 doses, we observed no effects on heart rate or body temperature after a single TA1 injection (50 mg·kg(-1) , i.p.) compared to sham-injected controls. Repeated administration of TA1 (5 mg·kg(-1) , i.p. for 7 days) likewise did not alter body weight, food and water intake, heart rate, blood pressure, brown adipose tissue (BAT) thermogenesis or body temperature. Moreover, mRNA expression of tissue specific genes in heart, kidney, liver, BAT and lung was also not altered by TA1 compared to sham-injected controls. Our data therefore conclusively demonstrate that TA1 does not contribute to the cardiovascular or thermoregulatory effects observed after 3-T1 AM administration in mice, suggesting that the oxidative deamination constitutes an important deactivation mechanism for 3-T1 AM with possible implications for cardiovascular and thermoregulatory functions. © 2015 The British Pharmacological Society.

  11. Protein and carbohydrate supplementation increases aerobic and thermoregulatory capacities

    PubMed Central

    Okazaki, Kazunobu; Goto, Masaki; Nose, Hiroshi

    2009-01-01

    The incidence of heat illness and heat stroke is greater in older than younger people. In this context, exercise training regimens to increase heat tolerance in older people may provide protection against heat illness. Acute increases in plasma volume (PV) improve thermoregulation during exercise in young subjects, but there is some evidence that changes in PV in response to acute exercise are blunted in older humans. We recently demonstrated that protein–carbohydrate (Pro-CHO) supplementation immediately after a bout of exercise increased PV and plasma albumin content (Albcont) after 23 h in both young and older subjects. We also examined whether Pro-CHO supplementation during aerobic training enhanced thermoregulation by increasing PV and Albcont in older subjects. Older men aged ∼68 years exercised at moderate intensity, 60 min day−1, 3 days week−1, for 8 weeks, at ∼19°C, and took either placebo (CNT; 0.5 kcal, 0 g protein kg−1) or Pro-CHO supplement (Pro-CHO; 3.2 kcal, 0.18 g protein kg−1) immediately after exercise. After training, we found during exercise at 30°C that increases in oesophageal temperature (Tes) were attenuated more in Pro-CHO than CNT and associated with enhanced cutaneous vasodilatation and sweating. We also confirmed similar results in young subjects after 5 days of training. These results demonstrate that post-exercise protein and CHO consumption enhance thermoregulatory adaptations especially in older subjects and provide insight into potential strategies to improve cardiovascular and thermoregulatory adaptations to exercise in both older and younger subjects. PMID:19752117

  12. Viscous fingering in a microfluidic network

    NASA Astrophysics Data System (ADS)

    Budek, Agnieszka; Garstecki, Piotr; Samborski, Adam; Szymczak, Piotr

    2014-05-01

    We study experimentally and numerically two-phase flow in a rectangular network of microfluidic channels. If the pressure gradient is oriented along the lattice, growth of long and thin dendrites ('thin fingers') is promoted. The dynamics of thin finger growth is of interest due to their appearance in a variety of other pattern forming systems, such as the growth of dendrites in electrochemical deposition experiments, channeling in dissolving rocks or side-branches growth in crystallization. Due to their simplicity, thin finger models are also attractive for theoretical analysis. A characteristic feature of these systems is a strong competition between the fingers which is a reflection of Saffman-Taylor instability acting in a nonlinear regime. Surprisingly, the case of miscible fluids turns out to be different, with the competition between the fingers hindered due to the strong lateral currents of the displaced fluid, which eventually cut off the heads of the advancing fingers, thus preventing their further growth. The heads continue to move through the system, preserving their shapes, thus forming the 'miscible droplets'. In immiscible case this process is hindered by the presence of the surface tension. A detailed analysis of this phenomenon is given with a particular emphasis on the scaling properties of the system.

  13. Multi-fingered robotic hand

    NASA Technical Reports Server (NTRS)

    Ruoff, Carl F. (Inventor); Salisbury, Kenneth, Jr. (Inventor)

    1990-01-01

    A robotic hand is presented having a plurality of fingers, each having a plurality of joints pivotally connected one to the other. Actuators are connected at one end to an actuating and control mechanism mounted remotely from the hand and at the other end to the joints of the fingers for manipulating the fingers and passing externally of the robot manipulating arm in between the hand and the actuating and control mechanism. The fingers include pulleys to route the actuators within the fingers. Cable tension sensing structure mounted on a portion of the hand are disclosed, as is covering of the tip of each finger with a resilient and pliable friction enhancing surface.

  14. A new mathematical model to simulate AVA cold-induced vasodilation reaction to local cooling.

    PubMed

    Rida, Mohamad; Karaki, Wafaa; Ghaddar, Nesreen; Ghali, Kamel; Hoballah, Jamal

    2014-11-01

    The purpose of this work was to integrate a new mathematical model with a bioheat model, based on physiology and first principles, to predict thermoregulatory arterio-venous anastomoses (AVA) and cold-induced vasodilation (CIVD) reaction to local cooling. The transient energy balance equations of body segments constrained by thermoregulatory controls were solved numerically to predict segmental core and skin temperatures, and arterial blood flow for given metabolic rate and environmental conditions. Two similar AVA-CIVD mechanisms were incorporated. The first was activated during drop in local skin temperature (<32 °C). The second mechanism was activated at a minimum finger skin temperature, T(CIVD, min), where the AVA flow is dilated and constricted once the skin temperature reached a maximum value. The value of T(CIVD,min) was determined empirically from values reported in literature for hand immersions in cold fluid. When compared with published data, the model predicted accurately the onset time of CIVD at 25 min and T(CIVD,min) at 10 °C for hand exposure to still air at 0 °C. Good agreement was also obtained between predicted finger skin temperature and experimentally published values for repeated immersion in cold water at environmental conditions of 30, 25, and 20 °C. The CIVD thermal response was found related to core body temperature, finger skin temperature, and initial finger sensible heat loss rate upon exposure to cold fluid. The model captured central and local stimulations of the CIVD and accommodated observed variability reported in literature of onset time of CIVD reaction and T(CIVD,min).

  15. Physiology of thermoregulatory dysfunction and current approaches to the treatment of vasomotor symptoms.

    PubMed

    Deecher, Darlene C

    2005-04-01

    Vasomotor symptoms (VMS), including hot flushes and night sweats, are the most common symptoms associated with menopause. Although the physiology of hot flushes is not fully defined, understanding the complex thermoregulatory circuitry that underlies VMS is important for the development of new therapies. This circuitry is composed of three distinct, yet interconnected, components: core body temperature, neurochemical messaging and peripheral vasculature. Evidence suggests that multiple physiological systems, including the neuroendocrine system, are important in the maintenance of thermoregulatory control. Causative roles of declining ovarian steroid levels in initiating thermoregulatory dysfunction are well documented. This paper reviews the physiology involved in the underlying thermoregulatory dysfunction that presumably causes VMS and discusses how this physiology relates to current and future VMS treatment options.

  16. An experimental test of the thermoregulatory hypothesis for the evolution of endothermy.

    PubMed

    Bennett, A F; Hicks, J W; Cullum, A J

    2000-10-01

    The thermoregulatory hypothesis proposes that endothermy in mammals and birds evolved as a thermoregulatory mechanism per se and that natural selection operated directly to increase body temperature and thermal stability through increments in resting metabolic rate. We experimentally tested this hypothesis by measuring the thermoregulatory consequences of increased metabolic rate in resting lizards (Varanus exanthematicus). A large metabolic increment was induced by feeding the animals and consequent changes in metabolic rate and body temperature were monitored. Although metabolic rate tripled at 32 degrees C and quadrupled at 35 degrees C, body temperature rose only about 0.5 degrees C. The rate of decline of body temperature in a colder environment did not decrease as metabolic rate increased. Thus, increasing the visceral metabolic rate of this ectothermic lizard established neither consequential endothermy nor homeothermy. These results are inconsistent with a thermoregulatory explanation for the evolution of endothermy.

  17. Three-Fingered Robot Hand

    NASA Technical Reports Server (NTRS)

    Ruoff, C. F.; Salisbury, J. K.

    1984-01-01

    Mechanical joints and tendons resemble human hand. Robot hand has three "human-like" fingers. "Thumb" at top. Rounded tips of fingers covered with resilient material provides high friction for griping. Hand potential as prosthesis for humans.

  18. Finger agnosia in Alzheimer disease.

    PubMed

    Shenal, Brian V; Jackson, Melissa D; Crucian, Gregory P; Heilman, Kenneth M

    2006-12-01

    The purpose of this study was to learn if a deficit of finger naming (finger agnosia or anomia) is a sensitive test for Alzheimer disease (AD) and the best means of testing for finger agnosia. The subjects were 38 patients with AD and 10 matched normal controls. All subjects were asked to name the thumb, index, and pinky fingers. No control subject had trouble naming any of these fingers, but 37% of the AD subjects did. When AD patients had difficulty with finger naming, they always had trouble naming the index finger. In the absence of stroke, the inability to name the index finger seems as an indicator of dementia. Although brief, this test is not extremely sensitive test for AD.

  19. Three-Fingered Robot Hand

    NASA Technical Reports Server (NTRS)

    Ruoff, C. F.; Salisbury, J. K.

    1984-01-01

    Mechanical joints and tendons resemble human hand. Robot hand has three "human-like" fingers. "Thumb" at top. Rounded tips of fingers covered with resilient material provides high friction for griping. Hand potential as prosthesis for humans.

  20. Spiral viscous fingering.

    NASA Astrophysics Data System (ADS)

    Nagatsu, Yuichiro; Hayashi, Atsushi; Kato, Yoshihito; Tada, Yutaka

    2006-11-01

    When a less-viscous fluid displaces a more-viscous fluid in a radial Hele-Shaw cell, viscous fingering pattern is believed to develop in a radial direction. We performed experiments on viscous fingering in a radial Hele-Shaw cell when a polymer solution, a sodium polyacrylate (SPA) solution is used as the more-viscous fluid and the trivalent iron (Fe^3+) solution is as the less-viscous fluid. The experiment was done by varying the concentration of Fe^3+, cFe3+. We have found that viscous fingering pattern develops spirally when cFe3+ is larger than a threshold value, while the pattern develops in a radial direction for small cFe3+. We confirmed from different experiments that an instantaneous chemical reaction takes place between SPA solution and Fe^3+ solution. The chemical reaction produces precipitation and significantly reduces the viscosity of the SPA solution. The quantity of the precipitation is increased with cFe3+. We will make a discussion on the relationship between the formation of spiral viscous fingering and the chemical reaction taking place between the two fluids.

  1. Finger Lakes LPG

    EPA Pesticide Factsheets

    Finger Lakes LPG Storage, LLC; Two Brush Creek Blvd, Suite 200; Kansas City; Missouri 64112 (Applicant) has applied to the U.S. Environmental Protection Agency (EPA) under the provisions of the Safe Drinking Water Act, 42 U.S.C. 300f et. seq (the Act), for

  2. Heart Failure and Thermoregulatory Control: Can Patients with Heart Failure Handle the Heat?

    PubMed

    Balmain, Bryce N; Sabapathy, Surendran; Jay, Ollie; Adsett, Julie; Stewart, Glenn M; Jayasinghe, Rohan; Morris, Norman R

    2017-04-10

    Upon heat exposure, the thermoregulatory system evokes reflex increases in sweating and skin blood flow responses to facilitate heat dissipation and maintain heat balance to prevent the continuing rise in core temperature. These heat dissipating responses are mediated primarily by autonomic and cardiovascular adjustments; which if attenuated, may compromise thermoregulatory control. In patients with heart failure (HF), the neurohumoral and cardiovascular dysfunction that underpins this condition may potentially impair thermoregulatory responses and, consequently, place these patients at a greater risk of heat-related illness. The aim of this review is to describe thermoregulatory mechanisms and the factors that may increase the risk of heat-related illness in patients with HF. An understanding of the mechanisms responsible for impaired thermoregulatory control in HF patients is of particular importance, given the current and projected increase in frequency and intensity of heat waves, as well as the promotion of regular exercise as a therapeutic modality. Furthermore, novel therapeutic strategies that may improve thermoregulatory control in HF, and the clinical relevance of this work in this population will be discussed.

  3. Anthropomorphic finger antagonistically actuated by SMA plates.

    PubMed

    Engeberg, Erik D; Dilibal, Savas; Vatani, Morteza; Choi, Jae-Won; Lavery, John

    2015-08-20

    Most robotic applications that contain shape memory alloy (SMA) actuators use the SMA in a linear or spring shape. In contrast, a novel robotic finger was designed in this paper using SMA plates that were thermomechanically trained to take the shape of a flexed human finger when Joule heated. This flexor actuator was placed in parallel with an extensor actuator that was designed to straighten when Joule heated. Thus, alternately heating and cooling the flexor and extensor actuators caused the finger to flex and extend. Three different NiTi based SMA plates were evaluated for their ability to apply forces to a rigid and compliant object. The best of these three SMAs was able to apply a maximum fingertip force of 9.01N on average. A 3D CAD model of a human finger was used to create a solid model for the mold of the finger covering skin. Using a 3D printer, inner and outer molds were fabricated to house the actuators and a position sensor, which were assembled using a multi-stage casting process. Next, a nonlinear antagonistic controller was developed using an outer position control loop with two inner MOSFET current control loops. Sine and square wave tracking experiments demonstrated minimal errors within the operational bounds of the finger. The ability of the finger to recover from unexpected disturbances was also shown along with the frequency response up to 7 rad s(-1). The closed loop bandwidth of the system was 6.4 rad s(-1) when operated intermittently and 1.8 rad s(-1) when operated continuously.

  4. Crustal fingering: solidification on a moving interface

    NASA Astrophysics Data System (ADS)

    Fu, Xiaojing; Jimenez-Martinez, Joaquin; Porter, Mark; Cueto-Felgueroso, Luis; Juanes, Ruben

    2016-11-01

    Viscous fingering-the hydrodynamic instability that takes place when a less viscous fluid displaces a more viscous fluid-is a well known phenomenon. Motivated by the formation of gas hydrates in seafloor sediments and during the ascent of gas bubbles through ocean water, here we study the interplay of immiscible viscous fingering with solidification of the evolving unstable interface. We present experimental observations of the dynamics of a bubble of Xenon in a water-filled and pressurized Hele-Shaw cell. The evolution is controlled by two processes: (1) the formation of a hydrate "crust" around the bubble, and (2) viscous fingering from bubble expansion. To reproduce the experimental observations, we propose a phase-field model that describes the nucleation and thickening of a porous solid shell on a moving gas-liquid interface. We design the free energy of the three-phase system (gas-liquid-hydrate) to rigorously account for interfacial effects, mutual solubility, and phase transformations (hydrate formation and disappearance). We introduce a pseudo-plasticity model with large variations in viscosity to describe the plate-like rheology of the hydrate shell. We present high-resolution numerical simulations of the model, which illustrate the emergence of complex "crustal fingering" patterns as a result of gas fingering dynamics modulated by hydrate growth at the interface.

  5. X-Ray Exam: Finger

    MedlinePlus

    ... Habits for TV, Video Games, and the Internet X-Ray Exam: Finger KidsHealth > For Parents > X-Ray Exam: Finger Print A A A What's in ... You Have Questions What It Is A finger X-ray is a safe and painless test that uses ...

  6. Relation between index finger width and hand width anthropometric measures.

    PubMed

    Komandur, Sashidharan; Johnson, Peter W; Storch, Richard L; Yost, Michael G

    2009-01-01

    Measures of hand and finger anthropometry are very important for designing many hand held devices as well as understanding anthropometric effects on the operation of such devices. Many historical datasets have measured and recorded gross hand dimensions but do not often record the finer dimensions of the hand such as finger anthropometry. Knowing the size and mass of fingers across genders can be critical to the design and operation of hand held devices. In this paper we compare two empirical linear models that predicts index finger width at the proximal interphalangeal (PIP) joint (a finger anthropometric measure) based on hand-width (hand anthropometric measure). This will be especially useful for deriving population measures of finger anthropometry from large historical data sets where only gross hand dimensions are available.

  7. Thermoregulatory demands of elite professional America's Cup yacht racing.

    PubMed

    Neville, V; Gant, N; Folland, J P

    2010-06-01

    America's Cup yacht racing predominantly occurs during the summer months under hot and humid conditions, with athletes exposed to the environment for prolonged periods, and yet the thermoregulatory responses to competitive sailing are largely unappreciated. This study aimed to assess the thermoregulatory responses to elite professional big-boat yacht racing, according to crew position and upwind and downwind sailing. Intestinal (T(core)) and skin temperature, fluid balance and regional sweat compositions were measured in two America's Cup crews (n=32) during 100 min of racing. The environmental conditions were as follows: 32 degrees C, 52% RH and 5 m/s wind speed. Subjective race intensity was moderate. Bowmen recorded the greatest elevation in the heart rate (184 +/- 10 beats/min) and T(core) (39.2 degrees C, P<0.01). Both heart rate and T(core) were higher during downwind sailing (P<0.001). Regional skin temperatures were significantly different according to site (P=0.05), with tibia being the lowest (33.3 +/- 1.2 degrees C). The mean sweat loss during racing was 1.34 +/- 0.58 L/h (range: 0.44-2.40 L/h), with bowmen experiencing the greatest loss of sweat (3.7 +/- 0.9% of body mass). The mean fluid intake was highly correlated to sweat loss (r=0.74, P<0.001), with 72 +/- 41% of sweat losses replaced. The mean sodium concentration of sweat was 27.2 +/- 9.2 mmol/L (range: 12.0-43.5 mmol/L) and the total NaCl loss during sailing was 3.8 +/- 2.4 g (range 0.7-10.0 g). America's Cup sailing is a demanding sport that presents considerable challenges to thermoregulation, fluid and electrolyte balance. Certain crew roles (bowmen) present an increased risk of developing exertional heat illness, and for the majority of crew downwind sailing results in greater thermal strain than upwind sailing - which may have implications for clothing selection and boat design.

  8. Safe Finger Tourniquet--Ideas.

    PubMed

    Wei, Lin-Gwei; Chen, Chieh-Feng; Hwang, Chun-Yuan; Chang, Chiung-Wen; Chiu, Wen-Kuan; Li, Chun-Chang; Wang, Hsian-Jenn

    2016-03-01

    Tourniquets are often needed for optimized phalangeal surgeries. However, few surgeons forget to remove them and caused ischemic injuries. We have a modified method to create a safe finger tourniquet for short duration finger surgeries, which can avoid such tragedy. It is done by donning a glove, cutting the tip of the glove over the finger of interest, and rolling the glove finger to the base. From 2010 to 2013, approximately 54 patients underwent digital surgical procedures with our safe finger tourniquet. Because the glove cannot be forgotten to be removed, the tourniquet must be released and removed. This is a simple and efficient way to apply a safe finger tourniquet by using hand rubber glove for a short-term bloodless finger surgery and can achieve an excellent surgical result.

  9. Hemangioma of the fingers.

    PubMed

    Kodachi, K; Kojima, T; Shimbashi, T; Furusato, M

    1990-01-01

    Fingers often suffer trauma and the clinician is continuously faced with the difficult task of clarifying the distinction between a hemangioma and a traumatic lesion. This study was undertaken to examine ten cases in which a small skin mass located on a finger had been diagnosed preoperatively as hemangioma. Our results showed that seven masses were confirmed pathologically as hemangioma (five cavernous hemangiomas and two capillary hemangiomas), two as traumatic thrombosis and one varix. The clinical manifestations of the two cases of traumatic thrombosis were related to those of hemangioma. In the varix, endothelial proliferation was observed in the area of the thrombosis. This phenomenon is called "intravascular papillary endothelial hyperplasia", and can confuse the differential diagnosis between a vascular neoplasm and a traumatic thrombosis. Our findings demonstrate that since the traumatic lesions were firmer than the hemangiomas, hardness on physical examination may be a helpful indicator in the differential diagnosis of a hemangioma and a traumatic lesion.

  10. Power Doppler signal calibration in the finger joint between two models of ultrasound machine: a pilot study using a phantom and joints in patients with rheumatoid arthritis.

    PubMed

    Sakano, Ryosuke; Saito, Katsumi; Kamishima, Tamotsu; Nishida, Mutsumi; Horie, Tatsunori; Noguchi, Atsushi; Kono, Michihito; Sutherland, Kenneth; Atsumi, Tatsuya

    2017-01-01

    Background Despite the advantages of ultrasound (US) in the management of rheumatoid arthritis (RA) patients, power Doppler (PD) US may be highly dependent on the type of US machine used. Purpose To present a method to calibrate the PD signal of two models of US machines by use of a flow phantom and finger joints of patients with RA. Material and Methods For the phantom study, the PD signal count was measured in the flow phantom perfusing blood mimicking fluid at various injection rates and pulse repetition frequencies (PRFs). The quantitative PD index was calculated with ImageJ. For the clinical study, the second and third metacarpophalangeal joints of five consecutive patients with RA were examined. The quantitative PD index was measured at various PRFs by use of two models of machine (the same models as the phantom study). Results For the phantom and clinical studies, negative correlations were found between the PRF and the quantitative PD index when the flow velocity was constant and positive correlations between flow velocity and the quantitative PD index at constant PRF. There was a significant difference in the depiction performance of synovial blood flow between the two models, which can be calibrated by adjusting the PRF values derived from the phantom study in each model. Conclusion Signal calibration of pannus vascularity between US machines may be possible by adjusting the PRF value according to flow phantom data. Different US machines can thus provide equivalent examination results concerning the pannus vascularity.

  11. Altered thermoregulatory responses to clonidine in streptozotocin-diabetic rats.

    PubMed Central

    O'Donnell, J. M.; Banyasz, T.; Kovacs, T.

    1996-01-01

    1. The effects of streptozotocin (STZ) treatment on alpha 2-adrenoceptor regulation of body temperature were studied by monitoring the response of colonic temperature to administration of clonidine. 2. A dose-dependent fall in colonic temperature occurred in control rats given clonidine challenge (0.05-2.0 mg kg-1, s.c.); this response was inhibited by prior administration of either yohimbine or idazoxan (2 mg kg-1, s.c.) but not by the peripherally-acting alpha 2-adrenoceptor antagonist L-659,066 (10 mg kg-1, s.c.). 3. In rats treated with STZ (65 mg kg-1, i.v.) administration of clonidine elicited a dose-independent hyperthermia (circa 1 degree C.); this effect was unaltered by prior administration of yohimbine or idazoxan. 4. Naloxone (5 mg kg-1, s.c.) elicited a small fall in temperature (< 1 degree C.) in both control and STZ-treated rats; naloxone pretreatment did not alter the temperature response to clonidine in either group. 5. Nicotinic acid (10 mg kg-1, s.c.) caused a similar small elevation in temperature in both groups. 6. Administration of replacement insulin to STZ-treated rats maintained weight gain and low blood glucose while the thermoregulatory response to clonidine slowly reverted to normal. 7. These results show that altered central temperature control is an element of the generalised abnormality of alpha 2-receptor function induced by STZ. PMID:8851514

  12. Altered thresholds for thermoregulatory sweating and vasodilatation in anorexia nervosa.

    PubMed Central

    Luck, P; Wakeling, A

    1980-01-01

    The changes in peripheral (hand) blood flow that occurred when deep body temperature was raised were measured in 13 patients with anorexia nervosa and 13 control subjects. The relation between blood flow and core temperature was shifted to the left in the patients with anorexia, with the onset of vasodilatation occurring at lower core and mean skin temperatures: no significant differences in the slopes of the responses were evident. The onset of thermal sweating occurred at lower core and mean skin temperatures in the patients with anorexia than in the controls. After ingestion of a high-energy liquid meal core temperature increased in the patients, and this was accompanied by a significant rise in peripheral blood flow in most cases. A similar meal in the normal subjects was followed by either no change in core temperature or a slight fall, and no consistent change in peripheral blood flow. These findings suggest that the lowering of thresholds for thermoregulatory sweating and vasodilatation may be a contributory factor to the abnormally low core temperature of patients with anorexia and may also explain some of their common complaints relating to feelings of warmth in the hands and feet after meals. PMID:7427504

  13. Effect of simulated microgravity exposure on thermoregulatory control of sweating.

    PubMed

    Michikami, D; Kamiya, A; Fu, Q; Niimi, Y; Iwase, S; Mano, T; Suzumura, A

    2001-12-01

    The purpose of the present study was to investigate the alterations in thermoregulatory control following 14 days of head-down bed rest (HDBR). The threshold temperature for sweating onset and sweating sensitivity were determined from sweating rates on the chest and forearm, and tympanic temperature as an index of core temperature (Tc) in nine healthy males exposed to a 60-min heat stress with a water-perfused blanket before and after HDBR. The threshold temperature for sweating onset, that is, the Tc at which sweating began on the chest and forearm was 36.75 +/- 0.14 and 36.72 +/- 0.13 degrees C before HDBR, respectively. The value significantly increased to 37.05 +/- 0.09 (p<0.05) for the chest and 37.04 +/- 0.08 degrees C (p<0.05) for the forearm after HDBR. On the other hand, the sweating sensitivity which was indicated as a slope of the Tc-sweating rate relationship significantly decreased from 4.20 +/- 1.15 to 2.32 +/- 1.18 for the chest (p<0.05) and from 4.20 +/- 1.06 to 2.92 +/- 0.98 mg/min/cm2/degrees C for the forearm (p<0.05) after HDBR. These findings suggest that the heat-dissipatory function was attenuated after 14 days of HDBR.

  14. Thermoregulatory responses to desert heat: age, race and sex.

    PubMed

    Yousef, M K; Dill, D B; Vitez, T S; Hillyard, S D; Goldman, A S

    1984-07-01

    Sixty-nine whites (38 men and 31 women) aged 17 to 88 years and 48 blacks (19 men and 29 women) aged 17 to 61 years were studied. Each person walked in desert heat for 1 hour at a rate requiring 40% of aerobic capacity. Observations were recorded on their rectal temperature (Tre), skin temperature (Tsk), heart rate (HR), blood pressure, and sweat rate (SR). Older men and women of both races were able to complete their walks without any ill effects. Age, per se, did not significantly reduce elderly individuals' ability to tolerate the combined stress of dry heat and exercise. Men of both races had higher sweat rate and lower heart rate and rectal and skin temperature than women working at the same percentage of aerobic capacity. Success of thermoregulation at 40% of aerobic capacity of blacks and whites was equal, but in both races men thermoregulated more successful than women. Our data suggest that thermoregulatory capacity of humans under desert conditions differs between sexes and is not influenced significantly by age or race except for differences in aerobic capacity.

  15. Thermoregulatory strategies in an aquatic ectotherm from thermally-constrained habitats: An evaluation of current approaches.

    PubMed

    Piasečná, Karin; Pončová, Alena; Tejedo, Miguel; Gvoždík, Lumír

    2015-08-01

    Many ectotherms employ diverse behavioral adjustments to effectively buffer the spatio-temporal variation in environmental temperatures, whereas others remain passive to thermal heterogeneity. Thermoregulatory studies are frequently performed on species living in thermally benign habitats, which complicate understanding of the thermoregulation-thermoconformity continuum. The need for new empirical data from ectotherms exposed to thermally challenging conditions requires the evaluation of available methods for quantifying thermoregulatory strategies. We evaluated the applicability of various thermoregulatory indices using fire salamander larvae, Salamandra salamandra, in two aquatic habitats, a forest pool and well, as examples of disparate thermally-constrained environments. Water temperatures in the well were lower and less variable than in the pool. Thermal conditions prevented larvae from reaching their preferred body temperature range in both water bodies. In contrast to their thermoregulatory abilities examined in a laboratory thermal gradient, field body temperatures only matched the mean and range of operative temperatures, showing thermal passivity of larvae in both habitats. Despite apparent thermoconformity, thermoregulatory indices indicated various strategies from active thermoregulation, to thermoconformity, and even thermal evasion, which revealed their limited applicability under thermally-constrained conditions. Salamander larvae abandoned behavioral thermoregulation despite varying opportunities to increase their body temperature above average water temperatures. Thermoconformity represents a favored strategy in these ectotherms living in more thermally-constrained environments than those examined in previous thermoregulatory studies. To understand thermal ecology and its impact on population dynamics, the quantification of thermoregulatory strategies of ectotherms in thermally-constrained habitats requires the careful choice of an appropriate

  16. The Effect of an Amino Acid Infusion on Central Thermoregulatory Control in Humans

    PubMed Central

    Nakajima, Yasufumi; Takamata, Akira; Matsukawa, Takashi; Sessler, Daniel I.; Kitamura, Yoshihiro; Ueno, Hiroshi; Tanaka, Yoshifumi; Mizobe, Toshiki

    2005-01-01

    Background Administration of protein or amino acids enhances thermogenesis, presumably by stimulating oxidative metabolism. However, hyperthermia results even when thermoregulatory responses are intact, suggesting that amino acids also alter central thermoregulatory control. We thus tested the hypothesis that amino acid infusion increases the thermoregulatory setpoint. Methods Nine male volunteers each participated on four study days in randomized order: 1) intravenous amino acids infused at 4 kJ·kg−1·hr−1 for 2.5 h combined with skin-surface warming; 2) amino acid infusion combined with cutaneous cooling; 3) a saline infusion combined with skin-surface warming; and, 4) saline infusion combined with cutaneous cooling. Results Amino acid infusion increased resting core temperature by 0.3 ± 0.1°C (mean ± SD) and oxygen consumption by 18 ± 12%. Furthermore, amino acid infusion increased the calculated core temperature threshold (triggering core temperature at a designated mean-skin temperature of 34°C) for active cutaneous vasodilation by 0.3 ± 0.3°C, for sweating by 0.2 ± 0.2°C, for thermoregulatory vasoconstriction by 0.3 ± 0.3°C, and for thermogenesis by 0.4 ± 0.5°C. Amino acid infusion did not alter the incremental response intensity (i.e., gain) of thermoregulatory defenses. Conclusions Amino acid infusion increased the metabolic rate and resting core temperature. However, amino acids also produced a synchronous increase in all major autonomic thermoregulatory defense thresholds; the increase in core temperature was identical to the setpoint increase — even in a cold environment with amble potential to dissipate heat. In subjects with intact thermoregulatory defenses, amino acid-induced hyperthermia appears to result from an elevated setpoint increase rather than increased metabolic rate per se. PMID:15108979

  17. Computer prediction of human thermoregulatory and temperature responses to a wide range of environmental conditions

    NASA Astrophysics Data System (ADS)

    Fiala, D.; Lomas, K. J.; Stohrer, M.

    A mathematical model for predicting human thermal and regulatory responses in cold, cool, neutral, warm, and hot environments has been developed and validated. The multi-segmental passive system, which models the dynamic heat transport within the body and the heat exchange between body parts and the environment, is discussed elsewhere. This paper is concerned with the development of the active system, which simulates the regulatory responses of shivering, sweating, and peripheral vasomotion of unacclimatised subjects. Following a comprehensive literature review, 26 independent experiments were selected that were designed to provoke each of these responses in different circumstances. Regression analysis revealed that skin and head core temperature affect regulatory responses in a non-linear fashion. A further signal, i.e. the rate of change of the mean skin temperature weighted by the skin temperature error signal, was identified as governing the dynamics of thermoregulatory processes in the cold. Verification and validation work was carried out using experimental data obtained from 90 exposures covering a range of steady and transient ambient temperatures between 5°C and 50°C and exercise intensities between 46 W/m2 and 600 W/m2. Good general agreement with measured data was obtained for regulatory responses, internal temperatures, and the mean and local skin temperatures of unacclimatised humans for the whole spectrum of climatic conditions and for different activity levels.

  18. Computer prediction of human thermoregulatory and temperature responses to a wide range of environmental conditions.

    PubMed

    Fiala, D; Lomas, K J; Stohrer, M

    2001-09-01

    A mathematical model for predicting human thermal and regulatory responses in cold, cool, neutral, warm, and hot environments has been developed and validated. The multi-segmental passive system, which models the dynamic heat transport within the body and the heat exchange between body parts and the environment, is discussed elsewhere. This paper is concerned with the development of the active system, which simulates the regulatory responses of shivering, sweating, and peripheral vasomotion of unacclimatised subjects. Following a comprehensive literature review, 26 independent experiments were selected that were designed to provoke each of these responses in different circumstances. Regression analysis revealed that skin and head core temperature affect regulatory responses in a nonlinear fashion. A further signal, i.e. the rate of change of the mean skin temperature weighted by the skin temperature error signal, was identified as governing the dynamics of thermoregulatory processes in the cold. Verification and validation work was carried out using experimental data obtained from 90 exposures covering a range of steady and transient ambient temperatures between 5 degrees C and 50 degrees C and exercise intensities between 46 W/m2 and 600 W/m2. Good general agreement with measured data was obtained for regulatory responses, internal temperatures, and the mean and local skin temperatures of unacclimatised humans for the whole spectrum of climatic conditions and for different activity levels.

  19. Effects Of Lake Warming On Behavioural Thermoregulatory Tactics In A Cold-Water Stenothermic Fish

    PubMed Central

    Goyer, Katerine; Bertolo, Andrea; Pépino, Marc; Magnan, Pierre

    2014-01-01

    Despite some evidence of within-population phenotypic variation in fish thermal behaviour, the occurrence of alternative tactics of this behaviour is rarely explicitly considered when studying natural populations. Brook charr provide an example of within-population variability in behavioural thermoregulation as revealed by a recent study on a lacustrine population of this species. The objectives of the present study were (i) to determine the influence of natural variability in the lake's thermal profiles on the expression of thermoregulatory tactics, and (ii) to determine the vertical and horizontal movements of individuals at different periods of the day to better understand the spatio-temporal behaviour associated with each thermoregulatory tactic. During summer 2010, 30 adult brook charr were equipped with thermo-sensitive radio transmitters to monitor their selected temperatures and daily movements. These individuals exhibited the same four behavioural thermoregulatory tactics observed in 2003 and 2005, but the expression of two of these was weaker in 2010. This result was associated with lake warming, which constrained the expression of two thermoregulatory tactics: brook charr significantly decreased their selected temperatures and daily movements when the mean daily epilimnion temperature was above 22.4°C. This study shows for the first time that the expression of behavioural thermoregulatory tactics is related to the lake's thermal regime and that the tactics are plastic through time. PMID:24663489

  20. Finger vein image quality evaluation using support vector machines

    NASA Astrophysics Data System (ADS)

    Yang, Lu; Yang, Gongping; Yin, Yilong; Xiao, Rongyang

    2013-02-01

    In an automatic finger-vein recognition system, finger-vein image quality is significant for segmentation, enhancement, and matching processes. In this paper, we propose a finger-vein image quality evaluation method using support vector machines (SVMs). We extract three features including the gradient, image contrast, and information capacity from the input image. An SVM model is built on the training images with annotated quality labels (i.e., high/low) and then applied to unseen images for quality evaluation. To resolve the class-imbalance problem in the training data, we perform oversampling for the minority class with random-synthetic minority oversampling technique. Cross-validation is also employed to verify the reliability and stability of the learned model. Our experimental results show the effectiveness of our method in evaluating the quality of finger-vein images, and by discarding low-quality images detected by our method, the overall finger-vein recognition performance is considerably improved.

  1. A biomechanical study of the finger pulley system during repair.

    PubMed

    Amirouche, F; Gonzalez, M; Koldoff, J; Tioco, J; Ham, K

    2002-01-01

    This paper addresses the mechanics of the finger/pulley system when subjected to various excisions and repairs. Several cadaver hands were used to study the finger/pulley's function, finger joint dynamics, and the relationship between tendon excursion and finger joint angles of rotation. By using a method of continuous and simultaneous data acquisition of the entire finger joint's motion, a more detailed analysis was achieved. Our experimental investigation is based on the use of four micro-potentiometers inserted at the finger's joints and a pulley system to simulate tendon excursion. Using this procedure, a detailed kinematic analysis of the entire finger was performed. This included analysis of the intact hand, various pulley excisions, and reconstruction. In addition to introducing a new method of acquisition, a mathematical model was developed for the inverse dynamic analysis of the finger pulley system. From this model, the torques required at the joints for the motion were computed. The results provided new insight into possible ways of characterizing kinematic changes resulting from pulley damage and repair.

  2. Robotic Finger Assembly

    NASA Technical Reports Server (NTRS)

    Ihrke, Chris A. (Inventor); Bridgwater, Lyndon (Inventor); Diftler, Myron A. (Inventor); Linn, Douglas M. (Inventor); Platt, Robert (Inventor); Hargrave, Brian (Inventor); Askew, Scott R. (Inventor); Valvo, Michael C. (Inventor)

    2013-01-01

    A robotic hand includes a finger with first, second, and third phalanges. A first joint rotatably connects the first phalange to a base structure. A second joint rotatably connects the first phalange to the second phalange. A third joint rotatably connects the third phalange to the second phalange. The second joint and the third joint are kinematically linked such that the position of the third phalange with respect to the second phalange is determined by the position of the second phalange with respect to the first phalange.

  3. Robotic Finger Assembly

    NASA Technical Reports Server (NTRS)

    Ihrke, Chris A. (Inventor); Bridgwater, Lyndon (Inventor); Diftler, Myron A. (Inventor); Linn, Douglas Martin (Inventor); Platt, Robert J., Jr. (Inventor); Hargrave, Brian (Inventor); Askew, Scott R. (Inventor); Valvo, Michael C. (Inventor)

    2014-01-01

    A robotic hand includes a finger with first, second, and third phalanges. A first joint rotatably connects the first phalange to a base structure. A second joint rotatably connects the first phalange to the second phalange. A third joint rotatably connects the third phalange to the second phalange. The second joint and the third joint are kinematically linked such that the position of the third phalange with respect to the second phalange is determined by the position of the second phalange with respect to the first phalange.

  4. Estimation of cardiac output and systemic vascular resistance using a multivariate regression model with features selected from the finger photoplethysmogram and routine cardiovascular measurements

    PubMed Central

    2013-01-01

    Background Cardiac output (CO) and systemic vascular resistance (SVR) are two important parameters of the cardiovascular system. The ability to measure these parameters continuously and noninvasively may assist in diagnosing and monitoring patients with suspected cardiovascular diseases, or other critical illnesses. In this study, a method is proposed to estimate both the CO and SVR of a heterogeneous cohort of intensive care unit patients (N=48). Methods Spectral and morphological features were extracted from the finger photoplethysmogram, and added to heart rate and mean arterial pressure as input features to a multivariate regression model to estimate CO and SVR. A stepwise feature search algorithm was employed to select statistically significant features. Leave-one-out cross validation was used to assess the generalized model performance. The degree of agreement between the estimation method and the gold standard was assessed using Bland-Altman analysis. Results The Bland-Altman bias ±precision (1.96 times standard deviation) for CO was -0.01 ±2.70 L min-1 when only photoplethysmogram (PPG) features were used, and for SVR was -0.87 ±412 dyn.s.cm-5 when only one PPG variability feature was used. Conclusions These promising results indicate the feasibility of using the method described as a non-invasive preliminary diagnostic tool in supervised or unsupervised clinical settings. PMID:23452705

  5. Gene correction by homologous recombination with zinc finger nucleases in primary cells from a mouse model of a generic recessive genetic disease.

    PubMed

    Connelly, Jon P; Barker, Jenny C; Pruett-Miller, Shondra; Porteus, Matthew H

    2010-06-01

    Zinc Finger nucleases (ZFNs) have been used to create precise genome modifications at frequencies that might be therapeutically useful in gene therapy. We created a mouse model of a generic recessive genetic disease to establish a preclinical system to develop the use of ZFN-mediated gene correction for gene therapy. We knocked a mutated GFP gene into the ROSA26 locus in murine embryonic stem (ES) cells and used these cells to create a transgenic mouse. We used ZFNs to determine the frequency of gene correction by gene targeting in different primary cells from this model. We achieved targeting frequencies from 0.17 to 6% in different cell types, including primary fibroblasts and astrocytes. We demonstrate that ex vivo gene-corrected fibroblasts can be transplanted back into a mouse where they retained the corrected phenotype. In addition, we achieved targeting frequencies of over 1% in ES cells, and the targeted ES cells retained the ability to differentiate into cell types from all three germline lineages. In summary, potentially therapeutically relevant frequencies of ZFN-mediated gene targeting can be achieved in a variety of primary cells and these cells can then be transplanted back into a recipient.

  6. Finger Forces in Clarinet Playing

    PubMed Central

    Hofmann, Alex; Goebl, Werner

    2016-01-01

    Clarinettists close and open multiple tone holes to alter the pitch of the tones. Their fingering technique must be fast, precise, and coordinated with the tongue articulation. In this empirical study, finger force profiles and tongue techniques of clarinet students (N = 17) and professional clarinettists (N = 6) were investigated under controlled performance conditions. First, in an expressive-performance task, eight selected excerpts from the first Weber Concerto were performed. These excerpts were chosen to fit in a 2 × 2 × 2 design (register: low–high; tempo: slow–fast, dynamics: soft–loud). There was an additional condition controlled by the experimenter, which determined the expression levels (low–high) of the performers. Second, a technical-exercise task, an isochronous 23-tone melody was designed that required different effectors to produce the sequence (finger-only, tongue-only, combined tongue-finger actions). The melody was performed in three tempo conditions (slow, medium, fast) in a synchronization-continuation paradigm. Participants played on a sensor-equipped Viennese clarinet, which tracked finger forces and reed oscillations simultaneously. From the data, average finger force (Fmean) and peak force (Fmax) were calculated. The overall finger forces were low (Fmean = 1.17 N, Fmax = 3.05 N) compared to those on other musical instruments (e.g., guitar). Participants applied the largest finger forces during the high expression level performance conditions (Fmean = 1.21 N). For the technical exercise task, timing and articulation information were extracted from the reed signal. Here, the timing precision of the fingers deteriorated the timing precision of the tongue for combined tongue-finger actions, especially for faster tempi. Although individual finger force profiles were overlapping, the group of professional players applied less finger force overall (Fmean = 0.54 N). Such sensor instruments provide useful insights into player

  7. Thermoregulatory plasticity in free-ranging vervet monkeys, Chlorocebus pygerythrus.

    PubMed

    Lubbe, Alwyn; Hetem, Robyn S; McFarland, Richard; Barrett, Louise; Henzi, Peter S; Mitchell, Duncan; Meyer, Leith C R; Maloney, Shane K; Fuller, Andrea

    2014-08-01

    We used implanted miniature data loggers to obtain the first measurements of body temperature from a free-ranging anthropoid primate. Vervet monkeys (Chlorocebus pygerythrus) living in a highly seasonal, semi-arid environment maintained a lower mean 24-h body temperature in winter (34.6 ± 0.5 °C) than in summer (36.2 ± 0.1 °C), and demonstrated increased heterothermy (as indexed by the 24-h amplitude of their body temperature rhythm) in response to proximal environmental stressors. The mean 24-h amplitude of the body temperature rhythm in summer (2.5 ± 0.1 °C) was lower than that in winter (3.2 ± 0.4 °C), with the highest amplitude for an individual monkey (5.6 °C) recorded in winter. The higher amplitude of the body temperature rhythm in winter was a consequence primarily of lower 24-h minimum body temperatures during the nocturnal phase, when monkeys were inactive. These low minimum body temperatures were associated with low black globe temperature (GLMM, β = 0.046, P < 0.001), short photoperiod (β = 0.010, P < 0.001) and low rainfall over the previous 2 months, which we used as a proxy for food availability (β = 0.001, P < 0.001). Despite the lower average winter minimum body temperatures, there was no change in the lower modal body temperature between winter and summer. Therefore, unlike the regulated physiological adjustments proposed for torpor or hibernation, these minimum winter body temperatures did not appear to reflect a regulated reduction in body temperature. The thermoregulatory plasticity nevertheless may have fitness benefits for vervet monkeys.

  8. Physical Effort Affects Heatstroke Thermoregulatory Response and Mortality in Rats.

    PubMed

    Geng, Yan; Peng, Na; Liu, Ya-Nan; Li, Xing-Gui; Li, Bing-Lin; Peng, Li-Qiong; Ma, Qiang; Su, Lei

    2015-08-01

    Animals suffering from heatstroke (HS) after physical effort may have different heat-related core temperature (Tc) responses compared with passive HS. In the present study, conscious and unrestrained rats were exposed to ambient temperature (Ta) of 39.5°C ± 0.2°C with or without running (run-heated or rest-heated, respectively) until HS onset, which was defined as the systolic blood pressure starting to drop. In comparison with rest-heated rats, run-heated rats had a significantly shorter latency of HS onset. Physical effort did not have significant influence on hyperthermia severity (43.3°C ± 0.2°C at rest-heated, and 43.4°C ± 0.2°C at run-heated), but it could significantly decrease the thermal load to develop HS (315.1°C ± 37.3°C·min for rest-heated, and 133.5 ± 21.4 °C·min for run-heated). Working component during heat exposure may contribute to a decreased survival rate of HS (46.9% at rest-heated and 31.3% at run-heated). Impaired heat dissipation during recovery may be responsible for relative poor survival of run-heated rats. In both groups, survival was affected by Tc at HS onset and thermal area. Hypothermia (Tc <35°C) developed after HS onset, with no significant difference in Tc,min between the rest-heated and run-heated groups. These thermoregulatory responses to HS after physical effort may provide insight into HS pathophysiology.

  9. Fibonacci-compliant finger design.

    PubMed

    El-Sheikh, Mogeeb A

    2016-11-11

    This work presents the mechanical design of 4 configurations of compliant fingers in order to address the need for commercially feasible prosthetic and robotic hands. The fingers consist of a single part and utilize a compliant mechanism to reduce the cost and control complexity. The geometric parameters of the compliant finger designs follow the Fibonacci series. The first and second compliant fingers have 2 joints and 2 degrees of freedom. The others have 3 joints and 3 degrees of freedom. The type of flexure hinges of the compliant finger are single and multiple nonsymmetrical circular hinges. The finite element method (FEM) was used to verify the range of motion of the joints in the compliant finger. In addition, the study defines the finger tip trajectory of these configurations. The multiple flexure hinges have minimum stress. This study presents affordable, single-element, compliant finger designs and their presumable hypothetical design variables are defined by the Fibonacci series. This method is faster and simpler than optimization. The study identifies the application of each finger design for either prosthetic or robotic purposes.

  10. Finger Injuries in Ball Sports.

    PubMed

    Netscher, David T; Pham, Dang T; Staines, Kimberly Goldie

    2017-02-01

    Finger injuries are common in athletes playing in professional ball sports. Understanding the intricate anatomy of the digit is necessary to properly diagnose and manage finger injuries. Unrecognized or poorly managed finger injuries can lead to chronic deformities that can affect an athlete's performance. Multiple factors and treatment options should be considered to provide the best functional outcome and rapid return to play for an athlete. This article discusses the mechanism of injury, diagnosis, treatment, and return-to-play recommendations for common finger injuries in ball sports.

  11. Tree-hugging koalas demonstrate a novel thermoregulatory mechanism for arboreal mammals

    PubMed Central

    Briscoe, Natalie J.; Handasyde, Kathrine A.; Griffiths, Stephen R.; Porter, Warren P.; Krockenberger, Andrew; Kearney, Michael R.

    2014-01-01

    How climate impacts organisms depends not only on their physiology, but also whether they can buffer themselves against climate variability via their behaviour. One of the way species can withstand hot temperatures is by seeking out cool microclimates, but only if their habitat provides such refugia. Here, we describe a novel thermoregulatory strategy in an arboreal mammal, the koala Phascolarctos cinereus. During hot weather, koalas enhanced conductive heat loss by seeking out and resting against tree trunks that were substantially cooler than ambient air temperature. Using a biophysical model of heat exchange, we show that this behaviour greatly reduces the amount of heat that must be lost via evaporative cooling, potentially increasing koala survival during extreme heat events. While it has long been known that internal temperatures of trees differ from ambient air temperatures, the relevance of this for arboreal and semi-arboreal mammals has not previously been explored. Our results highlight the important role of tree trunks as aboveground ‘heat sinks’, providing cool local microenvironments not only for koalas, but also for all tree-dwelling species. PMID:24899683

  12. Tree-hugging koalas demonstrate a novel thermoregulatory mechanism for arboreal mammals.

    PubMed

    Briscoe, Natalie J; Handasyde, Kathrine A; Griffiths, Stephen R; Porter, Warren P; Krockenberger, Andrew; Kearney, Michael R

    2014-06-01

    How climate impacts organisms depends not only on their physiology, but also whether they can buffer themselves against climate variability via their behaviour. One of the way species can withstand hot temperatures is by seeking out cool microclimates, but only if their habitat provides such refugia. Here, we describe a novel thermoregulatory strategy in an arboreal mammal, the koala Phascolarctos cinereus. During hot weather, koalas enhanced conductive heat loss by seeking out and resting against tree trunks that were substantially cooler than ambient air temperature. Using a biophysical model of heat exchange, we show that this behaviour greatly reduces the amount of heat that must be lost via evaporative cooling, potentially increasing koala survival during extreme heat events. While it has long been known that internal temperatures of trees differ from ambient air temperatures, the relevance of this for arboreal and semi-arboreal mammals has not previously been explored. Our results highlight the important role of tree trunks as aboveground 'heat sinks', providing cool local microenvironments not only for koalas, but also for all tree-dwelling species. © 2014 The Author(s) Published by the Royal Society. All rights reserved.

  13. Thermoregulatory behavior is widespread in the embryos of reptiles and birds.

    PubMed

    Li, Teng; Zhao, Bo; Zhou, Yong-Kang; Hu, Rui; Du, Wei-Guo

    2014-03-01

    Recent studies have demonstrated that thermoregulatory behavior occurs not only in posthatching turtles but also in turtles prior to hatching. Does thermoregulatory behavior also occur in the embryos of other reptile and bird species? Our experiments show that such behavior is widespread but not universal in reptile and bird embryos. We recorded repositioning within the egg, in response to thermal gradients, in the embryos of three species of snakes (Xenochrophis piscator, Elaphe bimaculata, and Zaocys dhumnades), two turtles (Chelydra serpentina and Ocadia sinensis), one crocodile (Alligator sinensis), and four birds (Coturnix coturnix, Gallus gallus domesticus, Columba livia domestica, and Anas platyrhynchos domestica). However, we detected no significant thermoregulation by the embryos of two lizard species (Takydromus septentrionalis and Phrynocephalus frontalis). Overall, embryonic thermoregulatory behavior is widespread in reptile as well as bird species but may be unimportant in the small eggs laid by most lizards.

  14. Anthropological and thermoregulatory changes induced by a survival sojourn in a tropical climate.

    PubMed

    Launay, Jean-Claude; Besnard, Yves; Sendowski, Isabelle; Guinet, Angélique; Hanniquet, Anne-Marie; Savourey, Gustave

    2002-01-01

    A survival sojourn in a tropical climate exposes subjects to 2 main constraints: food restriction and tropical climatic conditions. We hypothesized that such a sojourn could modify anthropological characteristics and thermoregulatory responses to heat and cold on return. Eight European male subjects were submitted to a sweating test (ST) for 90 minutes (dry bulb temperature [Tdb] = 47 degrees C, relative humidity (RH) = 10%, and wind speed = 0.8 m x s(-1)) and to a whole-body cold-air test (Tdb = 1 degrees C, RH = 40%, and wind speed = 0.8 m x s(-1)) for 120 minutes in thermoclimatic chambers both before and after a 4-week survival sojourn in French Guyana. The survival sojourn resulted in a decrease in lean body mass (P < .05) without any significant change in body fat content. Heat thermoregulatory changes studied during the ST were characterized both by a lower mean skin temperature (Tsk) (P < .05) and a higher sweat rate measured after the sojourn than before it (m(sw); P < .05). Cold thermoregulatory changes were characterized by a higher T(sk) value (P < .05) and a decreased onset for continuous shivering without any significant change in internal temperature or metabolic heat production (M). This study showed that this type of sojourn modifies not only biometrical characteristics of the subjects but also the thermoregulatory responses, inducing an adaptation of the thermoregulatory system to heat and an increase in the sensitivity of the thermoregulatory system to cold. This finding could have practical implications on return after such a sojourn.

  15. Repair of webbed fingers or toes

    MedlinePlus

    ... skin grafts Stiffness of the fingers or toes Injuries to the blood vessels, tendons, or bones in the fingers Call your provider if you notice the following: Fever Fingers that tingle, are numb, or have a bluish ... fingers or toes to protect the repaired area from injury. Small children who had webbed finger repair may ...

  16. Measurement and evaluation of finger tapping movements using magnetic sensors.

    PubMed

    Shima, Keisuke; Tsuji, Toshio; Kan, Eriko; Kandori, Akihiko; Yokoe, Masaru; Sakoda, Saburo

    2008-01-01

    This paper proposes a quantitative measurement and evaluation method of finger tapping movements for diagnosis support and assessment of motor function. In this method, a magnetic sensor consisting of two coils is used to measure movement. The coil voltage induced by the electromagnetic induction law changes depending on the distance between the two coils; this enables estimation of the distance between two coil-bearing fingertips from the voltage measured by the nonlinear modeling relationships between the voltages and distances. Further, the finger movements measured are evaluated by computing ten indices such as the finger tapping interval, and radar charts of the evaluation indices and phase-plane trajectories of the finger movements are then displayed in real time on a monitor. Evaluation experiments were performed on finger movement in 16 Parkinson's disease patients and 32 normal elderly subjects, with the results showing that all evaluation indices differ significantly for each subject (p < 0.05).

  17. Development of a CPM Machine for Injured Fingers.

    PubMed

    Fu, Yili; Zhang, Fuxiang; Ma, Xin; Meng, Qinggang

    2005-01-01

    Human fingers are easy to be injured. A CPM machine is a mechanism based on the rehabilitation theory of continuous passive motion (CPM). To develop a CPM machine for the clinic application in the rehabilitation of injured fingers is a significant task. Therefore, based on the theories of evidence based medicine (EBM) and CPM, we've developed a set of biomimetic mechanism after modeling the motions of fingers and analyzing its kinematics and dynamics analysis. We also design an embedded operating system based on ARM (a kind of 32-bit RISC microprocessor). The equipment can achieve the precise control of moving scope of fingers, finger's force and speed. It can serves as a rational checking method and a way of assessment for functional rehabilitation of human hands. Now, the first prototype has been finished and will start the clinical testing in Harbin Medical University shortly.

  18. Viscous fingering with partial miscible fluids

    NASA Astrophysics Data System (ADS)

    Fu, Xiaojing; Cueto-Felgueroso, Luis; Juanes, Ruben

    2015-11-01

    When a less viscous fluid displaces a more viscous fluid, the contrast in viscosity destabilizes the interface between the two fluids, leading to the formation of fingers. Studies of viscous fingering have focused on fluids that are either fully miscible or perfectly immiscible. In practice, however, the miscibility of two fluids can change appreciably with temperature and pressure, and often falls into the case of partial miscibility, where two fluids have limited solubility in each other. Following our recent work for miscible (Jha et al., PRL 2011, 2013) and immiscible systems (Cueto-Felgueroso and Juanes, PRL 2012, JFM 2014), here we propose a phase-field model for fluid-fluid displacements in a Hele-Shaw cell, when the two fluids have limited (but nonzero) solubility in one another. Partial miscibility is characterized through the design of thermodynamic free energy of the two-fluid system. We elucidate the key dimensionless groups that control the behavior of the system. We present high-resolution numerical simulations of the model applied to the viscous fingering problem. On one hand, we demonstrate the effect of partial miscibility on the hydrodynamic instability. On the other, we elucidate the role of the degree of fingering on the rate of mutual fluid dissolution.

  19. A Mathematical Model of Levodopa Medication Effect on Basal Ganglia in Parkinson's Disease: An Application to the Alternate Finger Tapping Task.

    PubMed

    Baston, Chiara; Contin, Manuela; Calandra Buonaura, Giovanna; Cortelli, Pietro; Ursino, Mauro

    2016-01-01

    Malfunctions in the neural circuitry of the basal ganglia (BG), induced by alterations in the dopaminergic system, are responsible for an array of motor disorders and milder cognitive issues in Parkinson's disease (PD). Recently Baston and Ursino (2015a) presented a new neuroscience mathematical model aimed at exploring the role of basal ganglia in action selection. The model is biologically inspired and reproduces the main BG structures and pathways, modeling explicitly both the dopaminergic and the cholinergic system. The present work aims at interfacing this neurocomputational model with a compartmental model of levodopa, to propose a general model of medicated Parkinson's disease. Levodopa effect on the striatum was simulated with a two-compartment model of pharmacokinetics in plasma joined with a motor effect compartment. The latter is characterized by the levodopa removal rate and by a sigmoidal relationship (Hill law) between concentration and effect. The main parameters of this relationship are saturation, steepness, and the half-maximum concentration. The effect of levodopa is then summed to a term representing the endogenous dopamine effect, and is used as an external input for the neurocomputation model; this allows both the temporal aspects of medication and the individual patient characteristics to be simulated. The frequency of alternate tapping is then used as the outcome of the whole model, to simulate effective clinical scores. Pharmacokinetic-pharmacodynamic modeling was preliminary performed on data of six patients with Parkinson's disease (both "stable" and "wearing-off" responders) after levodopa standardized oral dosing over 4 h. Results show that the model is able to reproduce the temporal profiles of levodopa in plasma and the finger tapping frequency in all patients, discriminating between different patterns of levodopa motor response. The more influential parameters are the Hill coefficient, related with the slope of the effect sigmoidal

  20. A Mathematical Model of Levodopa Medication Effect on Basal Ganglia in Parkinson's Disease: An Application to the Alternate Finger Tapping Task

    PubMed Central

    Baston, Chiara; Contin, Manuela; Calandra Buonaura, Giovanna; Cortelli, Pietro; Ursino, Mauro

    2016-01-01

    Malfunctions in the neural circuitry of the basal ganglia (BG), induced by alterations in the dopaminergic system, are responsible for an array of motor disorders and milder cognitive issues in Parkinson's disease (PD). Recently Baston and Ursino (2015a) presented a new neuroscience mathematical model aimed at exploring the role of basal ganglia in action selection. The model is biologically inspired and reproduces the main BG structures and pathways, modeling explicitly both the dopaminergic and the cholinergic system. The present work aims at interfacing this neurocomputational model with a compartmental model of levodopa, to propose a general model of medicated Parkinson's disease. Levodopa effect on the striatum was simulated with a two-compartment model of pharmacokinetics in plasma joined with a motor effect compartment. The latter is characterized by the levodopa removal rate and by a sigmoidal relationship (Hill law) between concentration and effect. The main parameters of this relationship are saturation, steepness, and the half-maximum concentration. The effect of levodopa is then summed to a term representing the endogenous dopamine effect, and is used as an external input for the neurocomputation model; this allows both the temporal aspects of medication and the individual patient characteristics to be simulated. The frequency of alternate tapping is then used as the outcome of the whole model, to simulate effective clinical scores. Pharmacokinetic-pharmacodynamic modeling was preliminary performed on data of six patients with Parkinson's disease (both “stable” and “wearing-off” responders) after levodopa standardized oral dosing over 4 h. Results show that the model is able to reproduce the temporal profiles of levodopa in plasma and the finger tapping frequency in all patients, discriminating between different patterns of levodopa motor response. The more influential parameters are the Hill coefficient, related with the slope of the effect

  1. Finger vein recognition based on finger crease location

    NASA Astrophysics Data System (ADS)

    Lu, Zhiying; Ding, Shumeng; Yin, Jing

    2016-07-01

    Finger vein recognition technology has significant advantages over other methods in terms of accuracy, uniqueness, and stability, and it has wide promising applications in the field of biometric recognition. We propose using finger creases to locate and extract an object region. Then we use linear fitting to overcome the problem of finger rotation in the plane. The method of modular adaptive histogram equalization (MAHE) is presented to enhance image contrast and reduce computational cost. To extract the finger vein features, we use a fusion method, which can obtain clear and distinguishable vein patterns under different conditions. We used the Hausdorff average distance algorithm to examine the recognition performance of the system. The experimental results demonstrate that MAHE can better balance the recognition accuracy and the expenditure of time compared with three other methods. Our resulting equal error rate throughout the total procedure was 3.268% in a database of 153 finger vein images.

  2. Differences in finger localisation performance of patients with finger agnosia.

    PubMed

    Anema, Helen A; Kessels, Roy P C; de Haan, Edward H F; Kappelle, L Jaap; Leijten, Frans S; van Zandvoort, Martine J E; Dijkerman, H Chris

    2008-09-17

    Several neuropsychological studies have suggested parallel processing of somatosensory input when localising a tactile stimulus on one's own by pointing towards it (body schema) and when localising this touched location by pointing to it on a map of a hand (body image). Usually these reports describe patients with impaired detection, but intact sensorimotor localisation. This study examined three patients with a lesion of the angular gyrus with intact somatosensory processing, but with selectively disturbed finger identification (finger agnosia). These patients performed normally when pointing towards the touched finger on their own hand but failed to indicate this finger on a drawing of a hand or to name it. Similar defects in the perception of other body parts were not observed. The findings provide converging evidence for the dissociation between body image and body schema and, more importantly, reveal for the first time that this distinction is also present in higher-order cognitive processes selectively for the fingers.

  3. Finger Movements in Transcription Typing

    DTIC Science & Technology

    1980-05-07

    learned motor movements.- DD , , 1473 00f n,.. ofo I. OV.o 95c ’ ~ 15 O,/BSOL."ETE, .[ -. 4 a/ 11L 1.5U NTARF~ SO. ~ ~ ~ ~ ~ ~ ~ ~ ~ ECRT AUSTRAC ...fingers. Sensory information and proprioceptive feedback from the mus- cles controlling the fingers could play a role . Neural impulses take about 70

  4. Skilled Finger Movements in Typing.

    ERIC Educational Resources Information Center

    Gentner, Donald R.

    Six skilled typists were studied while they transcribed English text. The typists showed stable patterns of performance, but with significant individual differences among themselves. Inter-keypress latencies for two-finger digraphs (typed by two fingers on the same hand) were particularly variable among typists. Two typists showed large…

  5. Gert Finger Becomes Emeritus Physicist

    NASA Astrophysics Data System (ADS)

    de Zeeuw, T.; Lucuix, C.; Péron, M.

    2016-03-01

    Gert Finger has retired after almost 33 years service and he has been made the first Emeritus Physicist at ESO. An appreciation of some of his many achievements in the development of infrared instrumentation and detector controllers is given. A retirement party for Gert Finger was held in February 2016.

  6. Viscous Fingers Driven by Oscillatory Pressure Drop Signals

    NASA Astrophysics Data System (ADS)

    Ledesma, Rodrigo; Corvera Poiré, Eugenia; Hernández-Machado, Aurora

    2004-03-01

    We study the response of the Saffman Taylor finger to a periodic force by means of a phase field model that was recently introduced for viscous fingers (1). A lateral instability on the sides of the finger develops, grows and coarsens. Sidebranching with wavelenght selection is obtained for a wide range of incident frequencies. (1) Phase-field model of Hele-Shaw flows in the high-viscosity contrast regime. A. Hernández-Machado, A.M. Lacasta, E.Mayoral and E. Corvera Poiré. Phys. Rev. E 68, 046310 (2003).

  7. Human thermoregulatory responses during heat exposure after artificially induced sunburn.

    PubMed

    Pandolf, K B; Gange, R W; Latzka, W A; Blank, I H; Kraning, K K; Gonzalez, R R

    1992-04-01

    Thermoregulatory responses in the heat (ambient temperature 49 degrees C, 20% relative humidity, 1 m/s wind) were investigated in 10 unacclimated men during 50 min of cycle ergometer exercise (approximately 53% of maximal aerobic power) after a 10-min rest before as well as 24 h and 1 wk after twice the minimal erythemal dose of UV-B radiation that covered approximately 85% of the body surface area. In 7 subjects esophageal temperature (Tes) was recorded while in all 10 subjects five-site skin and rectal temperatures, heart rate, and back, left forearm, and shielded (12 cm2 area) right forearm sweating rates (msw) were recorded at 15-s intervals. Venous blood was collected before and after exercise-heat stress. Mean skin temperature, Tes, rectal temperature, heart rate, and total body sweating rate were not significantly (P greater than 0.05) affected by sunburn. Pre- and postexercise values of hematocrit, hemoglobin, plasma protein, plasma volume, and plasma osmolality were also not affected (P greater than 0.05) by sunburn. Analysis of presunburn and post-sunburn data showed that the Tes intercept for sweating (degrees C) was unaffected (P greater than 0.05), but msw/Tes and final msw from the left forearm (msw/Tes 0.24 +/- 0.02 vs. 0.17 +/- 0.01 mg.cm-2.min-1. degrees C-1, P less than 0.05; msw 0.60 +/- 0.05 vs. 0.37 +/- 0.02, mg.cm-2.min-1, P less than 0.05) and back (msw/Tes 0.43 +/- 0.03 vs. 0.36 +/- 0.01 mg.cm-2.min-1. degrees C-1, P = 0.052; msw 1.08 +/- 0.09 vs. 0.74 +/- 0.05 mg.cm-2.min-1, P less than 0.05) were significantly reduced 24 h postsunburn.(ABSTRACT TRUNCATED AT 250 WORDS)

  8. Optimal three finger grasps

    NASA Technical Reports Server (NTRS)

    Demmel, J.; Lafferriere, G.

    1989-01-01

    Consideration is given to the problem of optimal force distribution among three point fingers holding a planar object. A scheme that reduces the nonlinear optimization problem to an easily solved generalized eigenvalue problem is proposed. This scheme generalizes and simplifies results of Ji and Roth (1988). The generalizations include all possible geometric arrangements and extensions to three dimensions and to the case of variable coefficients of friction. For the two-dimensional case with constant coefficients of friction, it is proved that, except for some special cases, the optimal grasping forces (in the sense of minimizing the dependence on friction) are those for which the angles with the corresponding normals are all equal (in absolute value).

  9. Comparison of Inter-Finger Connection Matrix Computation Techniques

    PubMed Central

    Martin, Joel R.; Terekhov, Alexander V.; Latash, Mark L.; Zatsiorsky, Vladimir M.

    2014-01-01

    A hypothesis was proposed that the central nervous system controls force production by the fingers through hypothetical neural commands (NCs). The NCs are scaled between values of 0 to 1, indicating no intentional force production or maximal voluntary contraction (MVC) force production, respectively. A matrix of finger inter-connections, [IFC], transforms NCs into finger forces. Two methods have been proposed to compute the [IFC]. The first method uses only single finger MVC trials and multiplies the [IFC] by a gain factor. The second method uses a neural network (NN) model based on experimental data. The performance of the two methods was compared on the MVC data and on a data set of sub-maximal forces, collected over a range of total forces and moments of force. The methods were compared in terms of: 1) ability to predict finger forces; 2) accuracy of NC reconstruction; and 3) preserved planarity of force data for sub-maximal force production task. Both methods did a reasonable job of predicting the total force in multi-finger MVC trials; however, the NN model performed better in regards to all other criteria. Overall, the results indicate that for modeling multi-finger interaction the NN method is preferable. PMID:23183029

  10. Acutely Decreased Thermoregulatory Energy Expenditure or Decreased Activity Energy Expenditure Both Acutely Reduce Food Intake in Mice

    PubMed Central

    Kaiyala, Karl J.; Morton, Gregory J.; Thaler, Joshua P.; Meek, Thomas H.; Tylee, Tracy; Ogimoto, Kayoko; Wisse, Brent E.

    2012-01-01

    Despite the suggestion that reduced energy expenditure may be a key contributor to the obesity pandemic, few studies have tested whether acutely reduced energy expenditure is associated with a compensatory reduction in food intake. The homeostatic mechanisms that control food intake and energy expenditure remain controversial and are thought to act over days to weeks. We evaluated food intake in mice using two models of acutely decreased energy expenditure: 1) increasing ambient temperature to thermoneutrality in mice acclimated to standard laboratory temperature or 2) exercise cessation in mice accustomed to wheel running. Increasing ambient temperature (from 21°C to 28°C) rapidly decreased energy expenditure, demonstrating that thermoregulatory energy expenditure contributes to both light cycle (40±1%) and dark cycle energy expenditure (15±3%) at normal ambient temperature (21°C). Reducing thermoregulatory energy expenditure acutely decreased food intake primarily during the light cycle (65±7%), thus conflicting with the delayed compensation model, but did not alter spontaneous activity. Acute exercise cessation decreased energy expenditure only during the dark cycle (14±2% at 21°C; 21±4% at 28°C), while food intake was reduced during the dark cycle (0.9±0.1 g) in mice housed at 28°C, but during the light cycle (0.3±0.1 g) in mice housed at 21°C. Cumulatively, there was a strong correlation between the change in daily energy expenditure and the change in daily food intake (R2 = 0.51, p<0.01). We conclude that acutely decreased energy expenditure decreases food intake suggesting that energy intake is regulated by metabolic signals that respond rapidly and accurately to reduced energy expenditure. PMID:22936977

  11. Modelling of the mechanical behavior of a polyurethane finger interphalangeal joint endoprosthesis after surface modification by ion implantation

    NASA Astrophysics Data System (ADS)

    Beliaev, A.; Svistkov, A.; Iziumov, R.; Osorgina, I.; Kondyurin, A.; Bilek, M.; McKenzie, D.

    2016-04-01

    Production of biocompatible implants made of polyurethane treated with plasma is very perspective. During plasma treatment the surface of polyurethane acquires unique physic-chemical properties. However such treatment may change the mechanical properties of polyurethane which may adversely affect the deformation behaviour of the real implant. Therefore careful study of the mechanical properties of the plasma-modified polyurethane is needed. In this paper, experimental observations of the elastic characteristics of plasma treated polyurethane and modelling of the deformation behaviour of polyurethane bio-implants are reported.

  12. Thermoregulatory responses in exercising rats: methodological aspects and relevance to human physiology

    PubMed Central

    Wanner, Samuel Penna; Prímola-Gomes, Thales Nicolau; Pires, Washington; Guimarães, Juliana Bohnen; Hudson, Alexandre Sérvulo Ribeiro; Kunstetter, Ana Cançado; Fonseca, Cletiana Gonçalves; Drummond, Lucas Rios; Damasceno, William Coutinho; Teixeira-Coelho, Francisco

    2015-01-01

    Rats are used worldwide in experiments that aim to investigate the physiological responses induced by a physical exercise session. Changes in body temperature regulation, which may affect both the performance and the health of exercising rats, are evident among these physiological responses. Despite the universal use of rats in biomedical research involving exercise, investigators often overlook important methodological issues that hamper the accurate measurement of clear thermoregulatory responses. Moreover, much debate exists regarding whether the outcome of rat experiments can be extrapolated to human physiology, including thermal physiology. Herein, we described the impact of different exercise intensities, durations and protocols and environmental conditions on running-induced thermoregulatory changes. We focused on treadmill running because this type of exercise allows for precise control of the exercise intensity and the measurement of autonomic thermoeffectors associated with heat production and loss. Some methodological issues regarding rat experiments, such as the sites for body temperature measurements and the time of day at which experiments are performed, were also discussed. In addition, we analyzed the influence of a high body surface area-to-mass ratio and limited evaporative cooling on the exercise-induced thermoregulatory responses of running rats and then compared these responses in rats to those observed in humans. Collectively, the data presented in this review represent a reference source for investigators interested in studying exercise thermoregulation in rats. In addition, the present data indicate that the thermoregulatory responses of exercising rats can be extrapolated, with some important limitations, to human thermal physiology. PMID:27227066

  13. Thermoregulatory responses in exercising rats: methodological aspects and relevance to human physiology.

    PubMed

    Wanner, Samuel Penna; Prímola-Gomes, Thales Nicolau; Pires, Washington; Guimarães, Juliana Bohnen; Hudson, Alexandre Sérvulo Ribeiro; Kunstetter, Ana Cançado; Fonseca, Cletiana Gonçalves; Drummond, Lucas Rios; Damasceno, William Coutinho; Teixeira-Coelho, Francisco

    2015-01-01

    Rats are used worldwide in experiments that aim to investigate the physiological responses induced by a physical exercise session. Changes in body temperature regulation, which may affect both the performance and the health of exercising rats, are evident among these physiological responses. Despite the universal use of rats in biomedical research involving exercise, investigators often overlook important methodological issues that hamper the accurate measurement of clear thermoregulatory responses. Moreover, much debate exists regarding whether the outcome of rat experiments can be extrapolated to human physiology, including thermal physiology. Herein, we described the impact of different exercise intensities, durations and protocols and environmental conditions on running-induced thermoregulatory changes. We focused on treadmill running because this type of exercise allows for precise control of the exercise intensity and the measurement of autonomic thermoeffectors associated with heat production and loss. Some methodological issues regarding rat experiments, such as the sites for body temperature measurements and the time of day at which experiments are performed, were also discussed. In addition, we analyzed the influence of a high body surface area-to-mass ratio and limited evaporative cooling on the exercise-induced thermoregulatory responses of running rats and then compared these responses in rats to those observed in humans. Collectively, the data presented in this review represent a reference source for investigators interested in studying exercise thermoregulation in rats. In addition, the present data indicate that the thermoregulatory responses of exercising rats can be extrapolated, with some important limitations, to human thermal physiology.

  14. Targeted mutagenesis of zebrafish: use of zinc finger nucleases.

    PubMed

    Leong, Ivone Un San; Lai, Daniel; Lan, Chuan-Ching; Johnson, Ross; Love, Donald R; Johnson, Ross; Love, Donald R

    2011-09-01

    The modeling of human disease in the zebrafish (Danio rerio) is moving away from chemical mutagensis and transient downregulation using morpholino oligomers to more targeted and stable transgenic methods. In this respect, zinc finger nucleases offer a means of introducing mutations at targeted sites at high efficiency. We describe here the development of zinc finger nucleases and their general use in model systems with a focus on the zebrafish.

  15. Use of zinc-finger nucleases to knock out the WAS gene in K562 cells: a human cellular model for Wiskott-Aldrich syndrome

    PubMed Central

    Toscano, Miguel G.; Anderson, Per; Muñoz, Pilar; Lucena, Gema; Cobo, Marién; Benabdellah, Karim; Gregory, Philip D.; Holmes, Michael C.; Martin, Francisco

    2013-01-01

    SUMMARY Mutations in the WAS gene cause Wiskott-Aldrich syndrome (WAS), which is characterized by eczema, immunodeficiency and microthrombocytopenia. Although the role of WASP in lymphocytes and myeloid cells is well characterized, its role on megakaryocyte (MK) development is poorly understood. In order to develop a human cellular model that mimics the megakaryocytic-derived defects observed in WAS patients we used K562 cells, a well-known model for study of megakaryocytic development. We knocked out the WAS gene in K562 cells using a zinc-finger nuclease (ZFN) pair targeting the WAS intron 1 and a homologous donor DNA that disrupted WASP expression. Knockout of WASP on K562 cells (K562WASKO cells) resulted in several megakaryocytic-related defects such as morphological alterations, lower expression of CD41ɑ, lower increments in F-actin polymerization upon stimulation, reduced CD43 expression and increased phosphatidylserine exposure. All these defects have been previously described either in WAS-knockout mice or in WAS patients, validating K562WASKO as a cell model for WAS. However, K562WASPKO cells showed also increased basal F-actin and adhesion, increased expression of CD61 and reduced expression of TGFβ and Factor VIII, defects that have never been described before for WAS-deficient cells. Interestingly, these phenotypic alterations correlate with different roles for WASP in megakaryocytic differentiation. All phenotypic alterations observed in K562WASKO cells were alleviated upon expression of WAS following lentiviral transduction, confirming the role of WASP in these phenotypes. In summary, in this work we have validated a human cellular model, K562WASPKO, that mimics the megakaryocytic-related defects found in WAS-knockout mice and have found evidences for a role of WASP as regulator of megakaryocytic differentiation. We propose the use of K562WASPKO cells as a tool to study the molecular mechanisms involved in the megakaryocytic-related defects observed

  16. Use of zinc-finger nucleases to knock out the WAS gene in K562 cells: a human cellular model for Wiskott-Aldrich syndrome.

    PubMed

    Toscano, Miguel G; Anderson, Per; Muñoz, Pilar; Lucena, Gema; Cobo, Marién; Benabdellah, Karim; Gregory, Philip D; Holmes, Michael C; Martin, Francisco

    2013-03-01

    Mutations in the WAS gene cause Wiskott-Aldrich syndrome (WAS), which is characterized by eczema, immunodeficiency and microthrombocytopenia. Although the role of WASP in lymphocytes and myeloid cells is well characterized, its role on megakaryocyte (MK) development is poorly understood. In order to develop a human cellular model that mimics the megakaryocytic-derived defects observed in WAS patients we used K562 cells, a well-known model for study of megakaryocytic development. We knocked out the WAS gene in K562 cells using a zinc-finger nuclease (ZFN) pair targeting the WAS intron 1 and a homologous donor DNA that disrupted WASP expression. Knockout of WASP on K562 cells (K562WASKO cells) resulted in several megakaryocytic-related defects such as morphological alterations, lower expression of CD41, lower increments in F-actin polymerization upon stimulation, reduced CD43 expression and increased phosphatidylserine exposure. All these defects have been previously described either in WAS-knockout mice or in WAS patients, validating K562WASKO as a cell model for WAS. However, K562WASPKO cells showed also increased basal F-actin and adhesion, increased expression of CD61 and reduced expression of TGFβ and Factor VIII, defects that have never been described before for WAS-deficient cells. Interestingly, these phenotypic alterations correlate with different roles for WASP in megakaryocytic differentiation. All phenotypic alterations observed in K562WASKO cells were alleviated upon expression of WAS following lentiviral transduction, confirming the role of WASP in these phenotypes. In summary, in this work we have validated a human cellular model, K562WASPKO, that mimics the megakaryocytic-related defects found in WAS-knockout mice and have found evidences for a role of WASP as regulator of megakaryocytic differentiation. We propose the use of K562WASPKO cells as a tool to study the molecular mechanisms involved in the megakaryocytic-related defects observed in WAS

  17. Dendrites, viscous fingers, and the theory of pattern formation

    NASA Technical Reports Server (NTRS)

    Langer, J. S.

    1989-01-01

    Recent developments in the theory of pattern formation in dendritic crystal growth and viscous fingering in fluids are reviewed. Consideration is given to the discovery that weak capillary forces act as singular perturbations which lead to selection mechanisms in dendritic crystal growth and fingering patterns. Other topics include the conventional thermodynamic model of the solidification of a pure substance from its melt, fingering instability, pattern selection, the solvability theory, dendritic growth rates, the bubble effect discovered by Couder et al. (1986), the dynamics of pattern-forming systems, and snowflake formation.

  18. Energy harvesting from mouse click of robot finger using piezoelectrics

    NASA Astrophysics Data System (ADS)

    Cha, Youngsu; Hong, Jin; Lee, Jaemin; Park, Jung-Min; Kim, Keehoon

    2017-04-01

    In this paper, we investigate the feasibility of energy harvesting from the mouse click motion using a piezoelectric energy transducer. Specifically, we use a robotic finger to realize repeatable mouse click motion. The robotic finger wears a glove with a pocket for including the piezoelectric material as an energy transducer. We propose a model for the energy harvesting system through the inverse kinematic framework of parallel joints in the finger and the electromechanical coupling equations of the piezoelectric material. Experiments are performed to elucidate the effect of the load resistance and the mouse click motion on energy harvesting.

  19. Finger-Circumference-Measuring Device

    NASA Technical Reports Server (NTRS)

    Le, Suy

    1995-01-01

    Easy-to-use device quickly measures circumference of finger (including thumb) on human hand. Includes polytetrafluoroethylene band 1/8 in. wide, bent into loop and attached to tab that slides on scale graduated in millimeters. Sliding tab preloaded with constant-force tension spring, which pulls tab toward closure of loop. Designed to facilitate measurements at various points along fingers to obtain data for studies of volumetric changes of fingers in microgravity. Also used in normal Earth gravity studies of growth and in assessment of diseases like arthritis.

  20. [Multiple finger geodes in children].

    PubMed

    Hoeffel, J C; Oprisescu, B; Bresson, A; Ploier, R; Vidailhet, M

    1993-06-01

    Three pediatric patients with multiple geodes in the fingers are reported. This condition occurs mainly between one and three years and at seven years of age and is more common in winter. Affected fingers are swollen. Roentgenograms disclose several small lucent defects which are usually located in the middle phalanx. Several fingers are usually involved. The erythrocyte sedimentation rate is increased in virtually every case. Resolution occurs spontaneously within a few weeks or months. There is no tendency towards recurrence. Although the condition is inflammatory, exposure to cold is probably a precipitating factor.

  1. Finger-Circumference-Measuring Device

    NASA Technical Reports Server (NTRS)

    Le, Suy

    1995-01-01

    Easy-to-use device quickly measures circumference of finger (including thumb) on human hand. Includes polytetrafluoroethylene band 1/8 in. wide, bent into loop and attached to tab that slides on scale graduated in millimeters. Sliding tab preloaded with constant-force tension spring, which pulls tab toward closure of loop. Designed to facilitate measurements at various points along fingers to obtain data for studies of volumetric changes of fingers in microgravity. Also used in normal Earth gravity studies of growth and in assessment of diseases like arthritis.

  2. Comparison of heat and cold stress to assess thermoregulatory dysfunction in hypothyroid rats.

    PubMed

    Gordon, C J; Becker, P; Padnos, B

    2000-12-01

    How borderline impairment of thyroid function can affect thermoregulation is an important issue because of the antithyroidal properties of a many environmental toxicants. This study compared the efficacy of heat and cold stress to identify thermoregulatory deficits in rats subjected to borderline and overt hypothyroidism via subchronic exposure to propylthiouracil (PTU). After 3 wk of exposure to PTU in the drinking water (0, 2.5, 5, 10, and 25 mg/l), rats were subjected to a heat stress challenge (34 degrees C for 2.5 h). After one more week of PTU treatment, the same rats were subjected to a cold stress challenge (7 degrees C for 2.5 h). Core temperature (T(c)) was monitored by radiotelemetry. Baseline T(c) during the light phase was reduced by treatment with 25 mg/l PTU. The rate of rise and overall increase in T(c) during heat stress was attenuated by PTU doses of 10 and 25 mg/l. Cold stress resulted in a 1.0 degrees C increase in T(c) regardless of PTU treatment. The rate of rise in T(c) during the cold stress challenge was similar in all PTU treatment groups. There was a dose-related decrease in serum thyroxine (T(4)) at PTU doses >/=5 mg/l. Serum triiodothyronine (T(3)) was reduced at PTU doses of 5 and 25 mg/l. Serum thyroid-stimulating hormone (TSH) was marginally elevated by PTU treatment. Overall, heat stress was more effective than cold stress for detecting a thermoregulatory deficit in borderline (i.e., 10 mg/l PTU) and overtly hypothyroid rats (i.e., 25 mg/l PTU). A significant thermoregulatory deficit is manifested with a 78% decrease in serum T(4). A thermoregulatory deficit is more correlated with a reduction in serum T(4) compared with T(3). Serum levels of TSH are unrelated to thermoregulatory response to heat and cold stress.

  3. Extreme plasticity in thermoregulatory behaviors of free-ranging black-tailed prairie dogs.

    PubMed

    Lehmer, Erin M; Savage, Lisa T; Antolin, Michael F; Biggins, Dean E

    2006-01-01

    In the natural environment, hibernating sciurids generally remain dormant during winter and enter numerous deep torpor bouts from the time of first immergence in fall until emergence in spring. In contrast, black-tailed prairie dogs (Cynomys ludovicianus) remain active throughout winter but periodically enter short and shallow bouts of torpor. While investigating body temperature (T(b)) patterns of black-tailed prairie dogs from six separate colonies in northern Colorado, we observed one population that displayed torpor patterns resembling those commonly seen in hibernators. Five individuals in this population experienced multiple torpor bouts in immediate succession that increased in length and depth as winter progressed, whereas 16 prairie dogs in five neighboring colonies remained euthermic for the majority of winter and entered shallow bouts of torpor infrequently. Our results suggest that these differences in torpor patterns did not result from differences in the physiological indicators that we measured because the prairie dogs monitored had similar body masses and concentrations of stored lipids across seasons. Likewise, our results did not support the idea that differences in overwinter T(b) patterns between prairie dogs in colonies with differing torpor patterns resulted from genetic differences between populations; genetic analyses of prairie dog colonies revealed high genetic similarity between the populations and implied that individuals regularly disperse between colonies. Local environmental conditions probably played a role in the unusual T(b) patterns experienced by prairie dogs in the colony where hibernation-like patterns were observed; this population received significantly less rainfall than neighboring colonies during the summer growing seasons before, during, and after the year of the winter in which they hibernated. Our study provides a rare example of extreme plasticity in thermoregulatory behaviors of free-ranging prairie dogs and provides

  4. Extreme plasticity in thermoregulatory behaviors of free-ranging black-tailed prairie dogs

    USGS Publications Warehouse

    Lehmer, E.M.; Savage, L.T.; Antolin, M.F.; Biggins, D.E.

    2006-01-01

    In the natural environment, hibernating sciurids generally remain dormant during winter and enter numerous deep torpor bouts from the time of first immergence in fall until emergence in spring. In contrast, black-tailed prairie dogs (Cynomys ludovicianus) remain active throughout winter but periodically enter short and shallow bouts of torpor. While investigating body temperature (Tb) patterns of black-tailed prairie dogs from six separate colonies in northern Colorado, we observed one population that displayed torpor patterns resembling those commonly seen in hibernators. Five individuals in this population experienced multiple torpor bouts in immediate succession that increased in length and depth as winter progressed, whereas 16 prairie dogs in five neighboring colonies remained euthermic for the majority of winter and entered shallow bouts of torpor infrequently. Our results suggest that these differences in torpor patterns did not result from differences in the physiological indicators that we measured because the prairie dogs monitored had similar body masses and concentrations of stored lipids across seasons. Likewise, our results did not support the idea that differences in overwinter Tb patterns between prairie dogs in colonies with differing torpor patterns resulted from genetic differences between populations; genetic analyses of prairie dog colonies revealed high genetic similarity between the populations and implied that individuals regularly disperse between colonies. Local environmental conditions probably played a role in the unusual T b patterns experienced by prairie dogs in the colony where hibernation-like patterns were observed; this population received significantly less rainfall than neighboring colonies during the summer growing seasons before, during, and after the year of the winter in which they hibernated. Our study provides a rare example of extreme plasticity in thermoregulatory behaviors of free-ranging prairie dogs and provides

  5. Analyses of thermoregulatory responses of feeder cattle exposed to simulated heat waves.

    PubMed

    Brown-Brandl, T M; Eigenberg, R A; Hahn, G L; Nienaber, J A; Mader, T L; Spiers, D E; Parkhurst, A M

    2005-05-01

    Heat stress in feedlot cattle causes reduced performance, and in the most severe cases, death of the animals, thus causing the loss of millions of dollars in revenue to the cattle industry. A study was designed to evaluate dynamics of thermoregulation and feeding activities when feeder cattle were exposed to simulated heat waves, in comparison with repeated sinusoidal hot and thermoneutral environments. Nine beef steers were randomly assigned to an individual pen in one of three environmental chambers. Each chamber was subjected to each of three temperature regimes (heatwave simulation from Rockport, Mo., 1995, heatwave simulation from Columbia, Mo., 1999, and Controlled heat stress treatment of 32+/-7 degrees C) for a period of 18 days, according to a Latin square treatment design, with a 10-day thermoneutral period (18+/-7 degrees C) separating treatment periods. Respiration rate, core body temperature, heat production, feed intake, and feeding behavior were measured on each animal for the duration of the experiment. Differences were found in all treatments for all parameters except feeding behavior. It was shown that the two simulated heat waves elicited very different thermoregulatory responses. Based on these results the heat wave centered at Rockport, Mo. in 1995 was devastating because the animals were not acclimated to hot conditions, thus causing an acute response to heat stress. The responses of cattle to conditions at Columbia, Mo. showed some acclimation to heat prior to the peak stress days, and therefore a dampened response was seen. It appears the extreme conditions at Columbia, Mo., 1999 were made severe by environmental conditions not simulated during this study (low wind speed and intensive solar radiation). Overall, it was determined while a cyclic heat stress treatment is a representative model to test heat stress in cattle, further heat stress experiments should be conducted in an actual feedlot.

  6. Neural correlates of finger gnosis.

    PubMed

    Rusconi, Elena; Tamè, Luigi; Furlan, Michele; Haggard, Patrick; Demarchi, Gianpaolo; Adriani, Michela; Ferrari, Paolo; Braun, Christoph; Schwarzbach, Jens

    2014-07-02

    Neuropsychological studies have described patients with a selective impairment of finger identification in association with posterior parietal lesions. However, evidence of the role of these areas in finger gnosis from studies of the healthy human brain is still scarce. Here we used functional magnetic resonance imaging to identify the brain network engaged in a novel finger gnosis task, the intermanual in-between task (IIBT), in healthy participants. Several brain regions exhibited a stronger blood oxygenation level-dependent (BOLD) response in IIBT than in a control task that did not explicitly rely on finger gnosis but used identical stimuli and motor responses as the IIBT. The IIBT involved stronger signal in the left inferior parietal lobule (IPL), bilateral precuneus (PCN), bilateral premotor cortex, and left inferior frontal gyrus. In all regions, stimulation of nonhomologous fingers of the two hands elicited higher BOLD signal than stimulation of homologous fingers. Only in the left anteromedial IPL (a-mIPL) and left PCN did signal strength decrease parametrically from nonhomology, through partial homology, to total homology with stimulation delivered synchronously to the two hands. With asynchronous stimulation, the signal was stronger in the left a-mIPL than in any other region, possibly indicating retention of task-relevant information. We suggest that the left PCN may contribute a supporting visuospatial representation via its functional connection to the right PCN. The a-mIPL may instead provide the core substrate of an explicit bilateral body structure representation for the fingers that when disrupted can produce the typical symptoms of finger agnosia.

  7. Multimodal biometric authentication based on the fusion of finger vein and finger geometry

    NASA Astrophysics Data System (ADS)

    Kang, Byung Jun; Park, Kang Ryoung

    2009-09-01

    We propose a new multimodal biometric recognition based on the fusion of finger vein and finger geometry. This research shows three novelties compared to previous works. First, this is the first approach to combine the finger vein and finger geometry information at the same time. Second, the proposed method includes a new finger geometry recognition based on the sequential deviation values of finger thickness extracted from a single finger. Third, we integrate finger vein and finger geometry by a score-level fusion method based on a support vector machine. Results show that recognition accuracy is significantly enhanced using the proposed method.

  8. Extensor mechanism of the fingers. I. A quantitative geometric study.

    PubMed

    Garcia-Elias, M; An, K N; Berglund, L; Linscheid, R L; Cooney, W P; Chao, E Y

    1991-11-01

    A close-range stereophotogrammetric measurement system was used to determine the three-dimensional geometric characteristics of the extensor assembly in seven human finger specimens and five finger configurations. The numerical data obtained showed that, although changes in length of the different bundles are small, their spatial orientation varies considerably from one to another position. This information should help to improve the accuracy of models derived to understand the extensor assembly behavior in normal and pathological conditions.

  9. Visual Foraging With Fingers and Eye Gaze.

    PubMed

    Jóhannesson, Ómar I; Thornton, Ian M; Smith, Irene J; Chetverikov, Andrey; Kristjánsson, Árni

    2016-03-01

    A popular model of the function of selective visual attention involves search where a single target is to be found among distractors. For many scenarios, a more realistic model involves search for multiple targets of various types, since natural tasks typically do not involve a single target. Here we present results from a novel multiple-target foraging paradigm. We compare finger foraging where observers cancel a set of predesignated targets by tapping them, to gaze foraging where observers cancel items by fixating them for 100 ms. During finger foraging, for most observers, there was a large difference between foraging based on a single feature, where observers switch easily between target types, and foraging based on a conjunction of features where observers tended to stick to one target type. The pattern was notably different during gaze foraging where these condition differences were smaller. Two conclusions follow: (a) The fact that a sizeable number of observers (in particular during gaze foraging) had little trouble switching between different target types raises challenges for many prominent theoretical accounts of visual attention and working memory. (b) While caveats must be noted for the comparison of gaze and finger foraging, the results suggest that selection mechanisms for gaze and pointing have different operational constraints.

  10. Visual Foraging With Fingers and Eye Gaze

    PubMed Central

    Thornton, Ian M.; Smith, Irene J.; Chetverikov, Andrey; Kristjánsson, Árni

    2016-01-01

    A popular model of the function of selective visual attention involves search where a single target is to be found among distractors. For many scenarios, a more realistic model involves search for multiple targets of various types, since natural tasks typically do not involve a single target. Here we present results from a novel multiple-target foraging paradigm. We compare finger foraging where observers cancel a set of predesignated targets by tapping them, to gaze foraging where observers cancel items by fixating them for 100 ms. During finger foraging, for most observers, there was a large difference between foraging based on a single feature, where observers switch easily between target types, and foraging based on a conjunction of features where observers tended to stick to one target type. The pattern was notably different during gaze foraging where these condition differences were smaller. Two conclusions follow: (a) The fact that a sizeable number of observers (in particular during gaze foraging) had little trouble switching between different target types raises challenges for many prominent theoretical accounts of visual attention and working memory. (b) While caveats must be noted for the comparison of gaze and finger foraging, the results suggest that selection mechanisms for gaze and pointing have different operational constraints. PMID:27433323

  11. Classification of finger vibrotactile input using scalp EEG.

    PubMed

    He, Yongtian; Contreras-Vidal, Jose L

    2015-01-01

    While there are many output brain-computer interface (output BCIs) studies, few have examined the input pathway, namely decoding the sensory input. To examine the possibility of building a BCI with sensory input using scalp electroencephalography (EEG), this study builds a classifier based on Local Fisher Discriminant Analysis (LFDA) and Gaussian Mixture Model (GMM) to classify neural activity generated by vibrotactile sensory stimuli delivered to the fingers. Small vibrators were placed on the fingertips of the participant. They vibrated one by one in a random sequence while the participant sat still with eyes closed. EEG data were recorded and later used to classify which finger was vibrated. There were two tasks: one focusing on differentiating between ipsilateral fingers, the other one focusing on differentiating contralateral fingers. Decoding accuracies were high in both tasks: 97.6% and 99.3% respectively. Event-related EEG features in both amplitude and power domain are discussed.

  12. Relative longitudinal motion of the finger flexors, subsynovial connective tissue, and median nerve before and after carpal tunnel release in a human cadaver model.

    PubMed

    Yamaguchi, Taihei; Osamura, Naoki; Zhao, Chunfeng; An, Kai-Nan; Amadio, Peter C

    2008-01-01

    The normal gliding environment in the carpal tunnel is complex. The median nerve and flexor tendons are surrounded by a multilayered subsynovial tissue. To date, observations of the relative motions of the flexor tendon, median nerve and multilayered subsynovial tissue have been through a surgically released open carpal tunnel. The purpose of this study was to compare the motions of these tissues in an intact and open carpal tunnel. We measured the relative motion of the middle finger flexor digitorum superficialis tendon, its surrounding subsynovial connective tissue (SSCT) and the median nerve in 8 human cadavers. The flexor retinaculum was used as a fixed reference point. The motions were compared for simulated isolated middle finger and simulated fist motion as measured fluoroscopically in the closed carpal tunnel and directly in the open carpal tunnel. While the simulated isolated finger motion produced significantly less SSCT and median nerve motion (p<.05), there was no difference in flexor digitorum superficialis, SSCT, or nerve motion when comparing the fluoroscopic measurements in the closed carpal tunnel with the direct visual measurements in the open carpal tunnel. Relative motion of the flexor tendons, SSCT, and median nerve within the carpal tunnel follows a certain pattern, which may indicate the physiological state of the SSCT. This relative motion pattern was not affected by flexor retinaculum release.

  13. Viscous fingering with partially miscible fluids

    NASA Astrophysics Data System (ADS)

    Fu, X.; Cueto-Felgueroso, L.; Juanes, R.

    2015-12-01

    When a less viscous fluid displaces a more viscous fluid, the contrast in viscosity destabilizes the interface between the two fluids, leading to the formation of fingers. Experimental and numerical studies of viscous fingering have focused on fluids that are either fully miscible (e.g. water and glycerol) or perfectly immiscible (e.g. water and oil). In practice, however, the miscibility of two fluids can change appreciably with temperature and pressure, and often falls into the case of partial miscibility, where two fluids have limited solubility in each other (e.g. CO2 and water). Following our recent work for miscible systems (Jha et al., PRL 2011, 2013) and immiscible systems (Cueto-Felgueroso and Juanes, PRL 2012, JFM 2014), here we propose a phase-field model for fluid-fluid displacements in a porous medium, when the two fluids have limited (but nonzero) solubility in one another. In our model, partial miscibility is characterized through the design of the thermodynamic free energy of the two-fluid system. We express the model in dimensionless form and elucidate the key dimensionless groups that control the behavior of the system. We present high-resolution numerical simulations of the model applied to the viscous fingering problem. On one hand, we demonstrate the effect of partial miscibility on the hydrodynamic instability. On the other, we elucidate the role of the degree of fingering on the rate of mutual fluid dissolution. Figure caption: final snapshots in simulations of viscous fingering with a two-fluid system mimicking that of CO2 and water. The colormap corresponds to the concentration of CO2. A band of less viscous gas phase rich in CO2 (red) displaces through the more viscous liquid phase that is undersaturated with CO2 (blue). At the fluid interface, an exchange of CO2 occurs as a result of local chemical potentials that drives the system towards thermodynamic equilibrium. This results in a shrinkage of gas phase as well as a local increase in

  14. Peripheral mechanisms of thermoregulatory control of skin blood flow in aged humans

    PubMed Central

    Kenney, W. Larry

    2010-01-01

    Human skin blood flow is controlled via dual innervation from the sympathetic nervous system. Reflex cutaneous vasoconstriction and vasodilation are both impaired with primary aging, rendering the aged more vulnerable to hypothermia and cardiovascular complications from heat-related illness. Age-related alterations in the thermoregulatory control of skin blood flow occur at multiple points along the efferent arm of the reflex, including 1) diminished sympathetic outflow, 2) altered presynaptic neurotransmitter synthesis, 3) reduced vascular responsiveness, and 4) impairments in downstream (endothelial and vascular smooth muscle) second-messenger signaling. This mechanistic review highlights some of the recent findings in the area of aging and the thermoregulatory control of skin blood flow. PMID:20413421

  15. Visual information without thermal energy may induce thermoregulatory-like cardiovascular responses.

    PubMed

    Takakura, Jun'ya; Nishimura, Takayuki; Watanuki, Shigeki

    2013-12-28

    Human core body temperature is kept quasi-constant regardless of varying thermal environments. It is well known that physiological thermoregulatory systems are under the control of central and peripheral sensory organs that are sensitive to thermal energy. If these systems wrongly respond to non-thermal stimuli, it may disturb human homeostasis. Fifteen participants viewed video images evoking hot or cold impressions in a thermally constant environment. Cardiovascular indices were recorded during the experiments. Correlations between the 'hot-cold' impression scores and cardiovascular indices were calculated. The changes of heart rate, cardiac output, and total peripheral resistance were significantly correlated with the 'hot-cold' impression scores, and the tendencies were similar to those in actual thermal environments corresponding to the impressions. The present results suggest that visual information without any thermal energy can affect physiological thermoregulatory systems at least superficially. To avoid such 'virtual' environments disturbing human homeostasis, further study and more attention are needed.

  16. Thermoregulatory Phenotype of the Trpv1 Knockout Mouse: Thermoeffector Dysbalance with Hyperkinesis

    PubMed Central

    Garami, Andras; Pakai, Eszter; Oliveira, Daniela L.; Steiner, Alexandre A.; Wanner, Samuel P.; Almeida, M. Camila; Lesnikov, Vladimir A.; Gavva, Narender R.; Romanovsky, Andrej A.

    2012-01-01

    This study aimed at determining the thermoregulatory phenotype of mice lacking transient receptor potential vanilloid-1 (TRPV1) channels. We used Trpv1 knockout (KO) mice and their genetically unaltered littermates to study diurnal variations in deep body temperature (Tb) and thermoeffector activities under basal conditions, as well as thermoregulatory responses to severe heat and cold. Only subtle alterations were found in the basal Tb of Trpv1 KO mice or in their Tb responses to thermal challenges. The main thermoregulatory abnormality of Trpv1 KO mice was a different pattern of thermoeffectors used to regulate Tb. On the autonomic side, Trpv1 KO mice were hypometabolic (had a lower oxygen consumption) and hypervasoconstricted (had a lower tail skin temperature). In agreement with the enhanced skin vasoconstriction, Trpv1 KO mice had a higher thermoneutral zone. On the behavioral side, Trpv1 KO mice preferred a lower ambient temperature and expressed a higher locomotor activity. Experiments with pharmacological TRPV1 agonists (resiniferatoxin and anandamide) and a TRPV1 antagonist (AMG0347) confirmed that TRPV1 channels located outside the brain tonically inhibit locomotor activity. With age (observed for up to 14 months), the body mass of Trpv1 KO mice exceeded that of controls, sometimes approaching 60 g. In summary, Trpv1 KO mice possess a distinct thermoregulatory phenotype, which is coupled with a predisposition to age-associated overweight and includes hypometabolism, enhanced skin vasoconstriction, decreased thermopreferendum, and hyperkinesis. The latter may be one of the primary deficiencies in Trpv1 KO mice. We propose that TRPV1-mediated signals from the periphery tonically suppress the general locomotor activity. PMID:21289181

  17. To each its own: Thermoregulatory strategy varies among neonatal polar phocids.

    PubMed

    Pearson, Linnea E; Liwanag, Heather E M; Hammill, Mike O; Burns, Jennifer M

    2014-12-01

    Cold environmental conditions and small body size promote heat loss and may create thermoregulatory challenges for marine mammals born in polar regions. However, among polar-born phocid seal species there are variations in physical attributes and environmental conditions at birth, allowing for an interesting contrast in thermoregulatory strategy. We compared thermoregulatory strategies through morphometrics, sculp attributes (conductivity and resistance), nonshivering thermogenesis (NST via uncoupling protein 1; UCP1), and muscle thermogenesis (via enzyme activity) in neonatal harp (Pagophilus groenlandicus), hooded (Cystophora cristata), and Weddell seals (Leptonychotes weddellii). Harp seals are the smallest at birth (9.8±0.7 kg), rely on lanugo (82.49±3.70% of thermal resistance), and are capable of NST through expression of UCP1 in brown adipose tissue (BAT). In contrast, hooded seal neonates (26.8±1.3 kg) have 2.06±0.23 cm of blubber, accounting for 38.19±6.07% of their thermal resistance. They are not capable of NST, as UCP1 is not expressed. The large Weddell seal neonates (31.5±4.9 kg) rely on lanugo (89.85±1.25% of thermal resistance) like harp seals, but no evidence of BAT was found. Muscle enzyme activity was highest in Weddell seal neonates, suggesting that they rely primarily on muscle thermogenesis. Similar total thermal resistance, combined with marked differences in thermogenic capacity of NST and ST among species, strongly supports that thermoregulatory strategy in neonatal phocids is more closely tied to pups' surface area to volume ratio (SA:V) and potential for early water immersion rather than mass and ambient environmental conditions.

  18. Circulatory and Thermoregulatory Actions of Hydration during Exercise-Heat Stress,

    DTIC Science & Technology

    1985-08-01

    6). %>. II. WATER LOSS In hot environments, body fluid is primarily lost via eccrine sweat gland secretion which enables evaporative cooling of the...hypohydration (12). .-- Eccrine sweat is ordinarily hypotonic relative to plasma. Therefore, the plasma will become hyperosmotic when hypohydration is...have .a direct CNS effect on the hypothalamic thermoregulatory centers or a peripheral effect on the eccrine sweat gland (3). Plasma volume loss’provides

  19. Thermal plasticity in young snakes: how will climate change affect the thermoregulatory tactics of ectotherms?

    PubMed

    Aubret, F; Shine, R

    2010-01-15

    Climate change will result in some areas becoming warmer and others cooler, and will amplify the magnitude of year-to-year thermal variation in many areas. How will such changes affect animals that rely on ambient thermal heterogeneity to behaviourally regulate their body temperatures? To explore this question, we raised 43 captive-born tiger snakes Notechis scutatus in enclosures that provided cold (19-22 degrees C), intermediate (19-26 degrees C) or hot (19-37 degrees C) thermal gradients. The snakes adjusted their diel timing of thermoregulatory behaviour so effectively that when tested 14 months later, body temperatures (mean and maximum), locomotor speeds and anti-predator behaviours did not differ among treatment groups. Thus, the young snakes modified their behaviour to compensate for restricted thermal opportunities. Then, we suddenly shifted ambient conditions to mimic year-to-year variation. In contrast to the earlier plasticity, snakes failed to adjust to this change, e.g. snakes raised at cooler treatments but then shifted to hot conditions showed a higher mean body temperature for at least two months after the onset of the new thermal regime. Hence, thermal conditions experienced early in life influenced subsequent thermoregulatory tactics; the mean selected temperature of a snake depended more upon its prior raising conditions than upon its current thermoregulatory opportunities. Behavioural plasticity thus allows snakes to adjust to suboptimal thermal conditions but this plasticity is limited. The major thermoregulatory challenge from global climate change may not be the shift in mean values (to which our young snakes adjusted) but the increased year-to-year variation (with which our snakes proved less able to deal).

  20. Can newts cope with the heat? Disparate thermoregulatory strategies of two sympatric species in water.

    PubMed

    Balogová, Monika; Gvoždík, Lumír

    2015-01-01

    Many ectotherms effectively reduce their exposure to low or high environmental temperatures using behavioral thermoregulation. In terrestrial ectotherms, thermoregulatory strategies range from accurate thermoregulation to thermoconformity according to the costs and limits of thermoregulation, while in aquatic taxa the quantification of behavioral thermoregulation have received limited attention. We examined thermoregulation in two sympatric newt species, Ichthyosaura alpestris and Lissotriton vulgaris, exposed to elevated water temperatures under semi-natural conditions. According to a recent theory, we predicted that species for which elevated water temperatures pose a lower thermal quality habitat, would thermoregulate more effectively than species in thermally benign conditions. In the laboratory thermal gradient, L. vulgaris maintained higher body temperatures than I. alpestris. Semi-natural thermal conditions provided better thermal quality of habitat for L. vulgaris than for I. alpestris. Thermoregulatory indices indicated that I. alpestris actively thermoregulated its body temperature, whereas L. vulgaris remained passive to the thermal heterogeneity of aquatic environment. In the face of elevated water temperatures, sympatric newt species employed disparate thermoregulatory strategies according to the species-specific quality of the thermal habitat. Both strategies reduced newt exposure to suboptimal water temperatures with the same accuracy but with or without the costs of thermoregulation. The quantification of behavioral thermoregulation proves to be an important conceptual and methodological tool for thermal ecology studies not only in terrestrial but also in aquatic ectotherms.

  1. Quantification of correlational selection on thermal physiology, thermoregulatory behavior, and energy metabolism in lizards.

    PubMed

    Artacho, Paulina; Saravia, Julia; Ferrandière, Beatriz Decencière; Perret, Samuel; Le Galliard, Jean-François

    2015-09-01

    Phenotypic selection is widely accepted as the primary cause of adaptive evolution in natural populations, but selection on complex functional properties linking physiology, behavior, and morphology has been rarely quantified. In ectotherms, correlational selection on thermal physiology, thermoregulatory behavior, and energy metabolism is of special interest because of their potential coadaptation. We quantified phenotypic selection on thermal sensitivity of locomotor performance (sprint speed), thermal preferences, and resting metabolic rate in captive populations of an ectothermic vertebrate, the common lizard, Zootoca vivipara. No correlational selection between thermal sensitivity of performance, thermoregulatory behavior, and energy metabolism was found. A combination of high body mass and resting metabolic rate was positively correlated with survival and negatively correlated with fecundity. Thus, different mechanisms underlie selection on metabolism in lizards with small body mass than in lizards with high body mass. In addition, lizards that selected the near average preferred body temperature grew faster that their congeners. This is one of the few studies that quantifies significant correlational selection on a proxy of energy expenditure and stabilizing selection on thermoregulatory behavior.

  2. Altered thermoregulatory responses after 15 days of head-down tilt

    NASA Technical Reports Server (NTRS)

    Crandall, Craig G.; Johnson, John M.; Convertino, Victor A.; Raven, Peter B.; Engelke, Keith A.

    1994-01-01

    To determine whether extended exposure to a simulation of microgravity alters thermoregulatory reflex control of skin blood flow, six adult males were exposed to 15 days of 6 deg head-down tilt (HDT). On an ambulatory control day before HDT exposure and on HDT day 15 the core temperature of each subject was increased by 0.5 - 1.0 C by whole body heating with a water-perfused suit. Mean skin temperature, oral temperature (T (sub or)), mean arterial pressure, and forearm blood flow were measured throughout the protocol. Forearm vascular conductance (FVC) was calculated from the ratio of forearm blood flow to mean arterial pressure. After HDT exposure, the T(sub or) threshold at which reflex thermally induced increases in FVC began was elevated, whereas the slope of the T(sub or)-FVC relationship after this threshold was reduced. Moreover, normothermic FVC and FVC at the highest common T(sub or) between pre- and post-HDT trials were reduced after HDT. These data suggest that HDT exposure reduces thermoregulatory responses to heat stress. The mechanisms resulting in such an impaired thermoregulatory response are unknown but are likely related to the relative dehydration that accompanies this exposure.

  3. Neural substrates for sexual and thermoregulatory behavior in the male leopard gecko, Eublepharis macularius.

    PubMed

    Edwards, Nora; Kriegsfeld, Lance; Crews, David

    2004-12-10

    The preoptic area-anterior hypothalamus (POAH) continuum is critical for the integration of environmental, physiological, and behavioral cues associated with reproduction in vertebrates. In the present study, radiofrequency lesions in the POAH abolished sexual behavior in the leopard gecko (Eublepharis macularius). Furthermore, results suggest a differential effect of POAH lesions on those behaviors regarded as appetitive (tail vibration and grip) and those regarded as consummatory (mounting and copulation), with consummatory behaviors being affected to a greater extent. E. macularius is an ectothermic vertebrate that modulates body temperature behaviorally relative to ambient temperature. In vertebrates, the POAH is also an important integrator of thermoregulation. Thus, the present study investigated whether lesions that disrupt reproductive behavior also disrupt body temperature regulation. While virtually all males displayed diurnal rhythms in thermoregulatory behavior prior to surgery, this pattern was abolished in a small proportion of animals bearing POAH lesions. Lesions that abolished thermoregulatory rhythms involved the suprachiasmatic nucleus (SCN), whereas lesions confined to the POAH, while dramatically influencing sexual behavior, did not affect thermoregulatory rhythms or temperature set point. Together, these findings identify the POAH as an important neural locus regulating sexual behavior but not thermoregulation and suggest that the SCN acts as a pacemaker controlling daily behavioral temperature regulation in this species.

  4. Can Newts Cope with the Heat? Disparate Thermoregulatory Strategies of Two Sympatric Species in Water

    PubMed Central

    Balogová, Monika; Gvoždík, Lumír

    2015-01-01

    Many ectotherms effectively reduce their exposure to low or high environmental temperatures using behavioral thermoregulation. In terrestrial ectotherms, thermoregulatory strategies range from accurate thermoregulation to thermoconformity according to the costs and limits of thermoregulation, while in aquatic taxa the quantification of behavioral thermoregulation have received limited attention. We examined thermoregulation in two sympatric newt species, Ichthyosaura alpestris and Lissotriton vulgaris, exposed to elevated water temperatures under semi-natural conditions. According to a recent theory, we predicted that species for which elevated water temperatures pose a lower thermal quality habitat, would thermoregulate more effectively than species in thermally benign conditions. In the laboratory thermal gradient, L. vulgaris maintained higher body temperatures than I. alpestris. Semi-natural thermal conditions provided better thermal quality of habitat for L. vulgaris than for I. alpestris. Thermoregulatory indices indicated that I. alpestris actively thermoregulated its body temperature, whereas L. vulgaris remained passive to the thermal heterogeneity of aquatic environment. In the face of elevated water temperatures, sympatric newt species employed disparate thermoregulatory strategies according to the species-specific quality of the thermal habitat. Both strategies reduced newt exposure to suboptimal water temperatures with the same accuracy but with or without the costs of thermoregulation. The quantification of behavioral thermoregulation proves to be an important conceptual and methodological tool for thermal ecology studies not only in terrestrial but also in aquatic ectotherms. PMID:25993482

  5. Thermoregulatory consequences of long-term microwave exposure at controlled ambient temperatures. Final report

    SciTech Connect

    Adair, E.R.; Spiers, D.E.; Rawson, R.O.; Adams, B.W.; Sheldon, D.K.

    1984-08-01

    The study was designed to identify and measure changes in thermoregulatory response systems, both behavioral and physiological, that may occur when squirrel monkeys are exposed to 2450-MHz CW microwaves 40 hours/week for 15 weeks. Microwave power densities explored were 1 and 5 mW/sq. cm. (SAR = 0.16 W/kg per mW/sq. cm.) and were presented at controlled environmental temperatures of 25, 30, and 35 C. Standardized tests, conducted periodically, assessed changes in thermoregulatory responses. Dependent variables measured included body mass, certain blood properties, metabolic heat production, sweating, skin temperatures, deep body temperature, and behavioral responses by which the monkeys selected a preferred environmental temperature. Results showed no alteration of metabolic rate, internal body temperature, or thermoregulatory behavior by microwave exposure although the ambient temperature prevailing during chronic exposure could exert an effect. An increase in sweating rate occurred in the 35 C environment, not enhanced significantly by microwave exposure. Skin temperature, reflecting vasomotor state, was reliably influenced by both ambient temperature and microwaves. The most robust consequence of microwave exposure was a reduction in body mass which appeared to be a function of microwave power density.

  6. Quantification of correlational selection on thermal physiology, thermoregulatory behavior, and energy metabolism in lizards

    PubMed Central

    Artacho, Paulina; Saravia, Julia; Ferrandière, Beatriz Decencière; Perret, Samuel; Le Galliard, Jean-François

    2015-01-01

    Phenotypic selection is widely accepted as the primary cause of adaptive evolution in natural populations, but selection on complex functional properties linking physiology, behavior, and morphology has been rarely quantified. In ectotherms, correlational selection on thermal physiology, thermoregulatory behavior, and energy metabolism is of special interest because of their potential coadaptation. We quantified phenotypic selection on thermal sensitivity of locomotor performance (sprint speed), thermal preferences, and resting metabolic rate in captive populations of an ectothermic vertebrate, the common lizard, Zootoca vivipara. No correlational selection between thermal sensitivity of performance, thermoregulatory behavior, and energy metabolism was found. A combination of high body mass and resting metabolic rate was positively correlated with survival and negatively correlated with fecundity. Thus, different mechanisms underlie selection on metabolism in lizards with small body mass than in lizards with high body mass. In addition, lizards that selected the near average preferred body temperature grew faster that their congeners. This is one of the few studies that quantifies significant correlational selection on a proxy of energy expenditure and stabilizing selection on thermoregulatory behavior. PMID:26380689

  7. Review on mallet finger treatment.

    PubMed

    Cheung, Jason Pui Yin; Fung, Boris; Ip, Wing Yuk

    2012-01-01

    Mallet finger is a common injury involving either an extensor tendon rupture at its insertion or an avulsion fracture involving the insertion of the terminal extensor tendon. It is usually caused by a forceful blow to the tip of the finger causing sudden flexion or a hyperextension injury. Fracture at the dorsal aspect of the base of the distal phalanx is commonly associated with palmar subluxation of the distal phalanx. Most mallet finger injuries are recommended to be treated with immobilisation of the distal interphalangeal joint in extension by splints. There is no consensus on the type of splint and the duration of use. Most studies have shown comparable results with different splints. Surgical fixation is still indicated in certain conditions such as open injuries, avulsion fracture involving at least one third of the articular surface with or without palmar subluxation of the distal phalanx and also failed splinting treatment.

  8. Biomechanical analysis of force distribution in human finger extensor mechanisms.

    PubMed

    Hu, Dan; Ren, Lei; Howard, David; Zong, Changfu

    2014-01-01

    The complexities of the function and structure of human fingers have long been recognised. The in vivo forces in the human finger tendon network during different activities are critical information for clinical diagnosis, surgical treatment, prosthetic finger design, and biomimetic hand development. In this study, we propose a novel method for in vivo force estimation for the finger tendon network by combining a three-dimensional motion analysis technique and a novel biomechanical tendon network model. The extensor mechanism of a human index finger is represented by an interconnected tendinous network moving around the phalanx's dorsum. A novel analytical approach based on the "Principle of Minimum Total Potential Energy" is used to calculate the forces and deformations throughout the tendon network of the extensor mechanism when subjected to an external load and with the finger posture defined by measurement data. The predicted deformations and forces in the tendon network are in broad agreement with the results obtained by previous experimental in vitro studies. The proposed methodology provides a promising tool for investigating the biomechanical function of complex interconnected tendon networks in vivo.

  9. Mesofluidic controlled robotic or prosthetic finger

    DOEpatents

    Lind, Randall F; Jansen, John F; Love, Lonnie J

    2013-11-19

    A mesofluidic powered robotic and/or prosthetic finger joint includes a first finger section having at least one mesofluidic actuator in fluid communication with a first actuator, a second mesofluidic actuator in fluid communication with a second actuator and a second prosthetic finger section pivotally connected to the first finger section by a joint pivot, wherein the first actuator pivotally cooperates with the second finger to provide a first mechanical advantage relative to the joint point and wherein the second actuator pivotally cooperates with the second finger section to provide a second mechanical advantage relative to the joint point.

  10. Fingering inside the coffee ring

    NASA Astrophysics Data System (ADS)

    Weon, Byung Mook; Je, Jung Ho

    2013-01-01

    Colloidal droplets including micro- and nanoparticles generally leave a ringlike stain, called the “coffee ring,” after evaporation. We show that fingering emerges during evaporation inside the coffee ring, resulting from a bidispersed colloidal mixture of micro- and nanoparticles. Microscopic observations suggest that finger formation is driven by competition between the coffee-ring and Marangoni effects, especially when the inward Marangoni flow is overwhelmed by the outward coffee-ring flow. This finding could help to understand the variety of the final deposition patterns of colloidal droplets.

  11. Prior Knowledge Improves Decoding of Finger Flexion from Electrocorticographic Signals

    PubMed Central

    Wang, Z.; Ji, Q.; Miller, K. J.; Schalk, Gerwin

    2011-01-01

    Brain–computer interfaces (BCIs) use brain signals to convey a user’s intent. Some BCI approaches begin by decoding kinematic parameters of movements from brain signals, and then proceed to using these signals, in absence of movements, to allow a user to control an output. Recent results have shown that electrocorticographic (ECoG) recordings from the surface of the brain in humans can give information about kinematic parameters (e.g., hand velocity or finger flexion). The decoding approaches in these studies usually employed classical classification/regression algorithms that derive a linear mapping between brain signals and outputs. However, they typically only incorporate little prior information about the target movement parameter. In this paper, we incorporate prior knowledge using a Bayesian decoding method, and use it to decode finger flexion from ECoG signals. Specifically, we exploit the constraints that govern finger flexion and incorporate these constraints in the construction, structure, and the probabilistic functions of the prior model of a switched non-parametric dynamic system (SNDS). Given a measurement model resulting from a traditional linear regression method, we decoded finger flexion using posterior estimation that combined the prior and measurement models. Our results show that the application of the Bayesian decoding model, which incorporates prior knowledge, improves decoding performance compared to the application of a linear regression model, which does not incorporate prior knowledge. Thus, the results presented in this paper may ultimately lead to neurally controlled hand prostheses with full fine-grained finger articulation. PMID:22144944

  12. Synergetic Fluid Mixing from Viscous Fingering and Alternating Injection

    NASA Astrophysics Data System (ADS)

    Jha, B.; Cueto-Felgueroso, L.; Juanes, R.

    2013-12-01

    We study mixing of two fluids of different viscosity in a microfluidic channel or porous medium. In recent work, we suggested that miscible viscous fingering--a hydrodynamic instability that takes place when a less viscous fluid displaces a more viscous fluid--can enhance mixing in Darcy flows, such as flows in Hele-Shaw cells or porous media [1]. Enhanced mixing due to viscous fingering emerges from the velocity disorder and the additional interfacial area created between the two fluids as a result of the hydrodynamic instability. Here, we show that the synergetic action of alternating injection and viscous fingering leads to a dramatic increase in mixing efficiency at high Péclet numbers. Based on observations from high-resolution simulations, we develop a theoretical model of mixing efficiency that combines a hyperbolic mixing model of the channelized region ahead, and a mixing-dissipation model of the pseudo-steady region behind. Our macroscopic model quantitatively reproduces the evolution of the average degree of mixing along the flow direction, and can be used as a design tool to optimize mixing from viscous fingering in a microfluidic channel. [1] B. Jha, L. Cueto-Felgueroso and R. Juanes, Fluid mixing from viscous fingering, Physical Review Letters, 106, 194502 (2011).

  13. Compatibility between observed and executed finger movements: comparing symbolic, spatial, and imitative cues.

    PubMed

    Brass, M; Bekkering, H; Wohlschläger, A; Prinz, W

    2000-11-01

    Intuitively, one can assume that imitating a movement is an easier task than responding to a symbolic stimulus like a verbal instruction. Support for this suggestion can be found in neuropsychological research as well as in research on stimulus-response compatibility. However controlled experimental evidence for this assumption is still lacking. We used a stimulus-response compatibility paradigm to test the assumption. In a series of experiments, it was tested whether observed finger movements have a stronger influence on finger movement execution than a symbolic or spatial cue. In the first experiment, we compared symbolic cues with observed finger movements using an interference paradigm. Observing finger movements strongly influenced movement execution, irrespective of whether the finger movement was the relevant or the irrelevant stimulus dimension. In the second experiment, effects of observed finger movements and spatial finger cues were compared. The observed finger movement dominated the spatial finger cue. A reduction in the similarity of observed and executed action in the third experiment led to a decrease of the influence of observed finger movement, which demonstrates the crucial role of the imitative relation of observed and executed action for the described effects. The results are discussed in relation to recent models of stimulus-response compatibility. Neurocognitive support for the strong relationship between movement observation and movement execution is reported. Copyright 2000 Academic Press.

  14. 'Frozen finger' in anal fissures.

    PubMed

    Chintamani; Tandon, Megha; Khandelwal, Rohan

    2009-10-01

    Acute anal fissures are usually managed by various invasive and non-invasive modalities ranging from simple lifestyle changes to chemical and surgical sphincterotomies. Frozen finger, prepared using a water-filled ordinary rubber glove, was successfully used in one hundred patients, thus providing a cost-effective and simple solution to the problem.

  15. Interaction of three-finger proteins from snake venoms and from mammalian brain with the cys-loop receptors and their models.

    PubMed

    Faure, G; Shelukhina, I V; Porowinska, D; Shulepko, M A; Lyukmanova, E N; Dolgikh, D A; Spirova, E N; Kasheverov, I E; Utkin, Yu N; Corringer, J-P; Tsetlin, V I

    2016-05-01

    With the use of surface plasmon resonance (SPR) it was shown that ws-Lynx1, a water-soluble analog of the three-finger membrane-bound protein Lynx1, that modulates the activity of brain nicotinic acetylcholine receptors (nAChRs), interacts with the acetylcholine-binding protein (AChBP) with high affinity, K D = 62 nM. This result agrees with the earlier demonstrated competition of ws-Lynx1 with radioiodinated α-bungarotoxin for binding to AChBP. For the first time it was shown that ws-Lynx1 binds to GLIC, prokaryotic Cys-loop receptor (K D = 1.3 μM). On the contrary, SPR revealed that α-cobratoxin, a three-finger protein from cobra venom, does not bind to GLIC. Obtained results indicate that SPR is a promising method for analysis of topography of ws-Lynx1 binding sites using its mutants and those of AChBP and GLIC.

  16. Making fingers and words count in a cognitive robot

    PubMed Central

    De La Cruz, Vivian M.; Di Nuovo, Alessandro; Di Nuovo, Santo; Cangelosi, Angelo

    2013-01-01

    Evidence from developmental as well as neuroscientific studies suggest that finger counting activity plays an important role in the acquisition of numerical skills in children. It has been claimed that this skill helps in building motor-based representations of number that continue to influence number processing well into adulthood, facilitating the emergence of number concepts from sensorimotor experience through a bottom-up process. The act of counting also involves the acquisition and use of a verbal number system of which number words are the basic building blocks. Using a Cognitive Developmental Robotics paradigm we present results of a modeling experiment on whether finger counting and the association of number words (or tags) to fingers, could serve to bootstrap the representation of number in a cognitive robot, enabling it to perform basic numerical operations such as addition. The cognitive architecture of the robot is based on artificial neural networks, which enable the robot to learn both sensorimotor skills (finger counting) and linguistic skills (using number words). The results obtained in our experiments show that learning the number words in sequence along with finger configurations helps the fast building of the initial representation of number in the robot. Number knowledge, is instead, not as efficiently developed when number words are learned out of sequence without finger counting. Furthermore, the internal representations of the finger configurations themselves, developed by the robot as a result of the experiments, sustain the execution of basic arithmetic operations, something consistent with evidence coming from developmental research with children. The model and experiments demonstrate the importance of sensorimotor skill learning in robots for the acquisition of abstract knowledge such as numbers. PMID:24550795

  17. Inheritance of finger pattern types in MZ and DZ twins.

    PubMed

    Karmakar, B; Malkin, I; Kobyliansky, E

    2011-08-01

    Digital patterns of a sample on twins were analyzed to estimate the resemblance between monozygotic (MZ) and dizygotic (DZ) twins and to evaluate the mode of inheritance by the use of maximum likelihood based variance decomposition analysis. MZ twin resemblance of finger pattern types appears to be more pronounced than in DZ twins, which suggests the presence of genetic factors in the forming of fingertip patterns. The most parsimonious model shows twin resemblance in count of all three basic finger patterns on 10 fingers. It has significant dominant genetic variance component across all fingers. In the general model, the dominant genetic variance component proportion is similar for all fingertips (about 60%) and the sibling environmental variance is significantly nonzero, but the proportion between additive and dominant variance components was different. Application of genetic model fitting technique of segregation analyses clearly shows mode of inheritance. A dominant genetic variance component or a specific genetic system modifies the phenotypic expression of the fingertip patterns. The present study provided evidence of strong genetic component in finger pattern types and seems more informative compared to the earlier traditional method of correlation analysis. Copyright © 2011. Published by Elsevier GmbH.

  18. Finger posture modulates structural body representations

    PubMed Central

    Tamè, Luigi; Dransfield, Elanah; Quettier, Thomas; Longo, Matthew R.

    2017-01-01

    Patients with lesions of the left posterior parietal cortex commonly fail in identifying their fingers, a condition known as finger agnosia, yet are relatively unimpaired in sensation and skilled action. Such dissociations have traditionally been interpreted as evidence that structural body representations (BSR), such as the body structural description, are distinct from sensorimotor representations, such as the body schema. We investigated whether performance on tasks commonly used to assess finger agnosia is modulated by changes in hand posture. We used the ‘in between’ test in which participants estimate the number of unstimulated fingers between two touched fingers or a localization task in which participants judge which two fingers were stimulated. Across blocks, the fingers were placed in three levels of splay. Judged finger numerosity was analysed, in Exp. 1 by direct report and in Exp. 2 as the actual number of fingers between the fingers named. In both experiments, judgments were greater when non-adjacent stimulated fingers were positioned far apart compared to when they were close together or touching, whereas judgements were unaltered when adjacent fingers were stimulated. This demonstrates that BSRs are not fixed, but are modulated by the real-time physical distances between body parts. PMID:28223685

  19. 27 CFR 9.34 - Finger Lakes.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 27 Alcohol, Tobacco Products and Firearms 1 2013-04-01 2013-04-01 false Finger Lakes. 9.34 Section... Lakes. (a) Name. The name of the viticultural area described in this section is “Finger Lakes.” (b) Approved maps. The appropriate maps for determining the boundaries of the Finger Lakes viticultural area...

  20. Generation of dense plume fingers in saturated-unsaturated homogeneous porous media

    NASA Astrophysics Data System (ADS)

    Cremer, Clemens J. M.; Graf, Thomas

    2015-02-01

    Flow under variable-density conditions is widespread, occurring in geothermal reservoirs, at waste disposal sites or due to saltwater intrusion. The migration of dense plumes typically results in the formation of vertical plume fingers which are known to be triggered by material heterogeneity or by variations in source concentration that causes the density variation. Using a numerical groundwater model, six perturbation methods are tested under saturated and unsaturated flow conditions to mimic heterogeneity and concentration variations on the pore scale in order to realistically generate dense fingers. A laboratory-scale sand tank experiment is numerically simulated, and the perturbation methods are evaluated by comparing plume fingers obtained from the laboratory experiment with numerically simulated fingers. Dense plume fingering for saturated flow can best be reproduced with a spatially random, time-constant perturbation of the solute source. For unsaturated flow, a spatially and temporally random noise of solute concentration or a random conductivity field adequately simulate plume fingering.

  1. Control of Grasp and Manipulation by Soft Fingers with 3-Dimensional Deformation

    NASA Astrophysics Data System (ADS)

    Nakashima, Akira; Shibata, Takeshi; Hayakawa, Yoshikazu

    In this paper, we consider control of grasp and manipulation of an object in a 3-dimensional space by a 3-fingered hand robot with soft finger tips. We firstly propose a 3-dimensional deformation model of a hemispherical soft finger tip and verify its relevance by experimental data. Second, we consider the contact kinematics and derive the dynamical equations of the fingers and the object where the 3-dimensional deformation is considered. For the system, we thirdly propose a method to regulate the object and the internal force with the information of the hand, the object and the deformation. A simulation result is presented to show the effectiveness of the control method.

  2. Clay for Little Fingers.

    ERIC Educational Resources Information Center

    Koster, Joan Bouza

    1999-01-01

    Discusses the renewed interest in clay as a modeling compound in early childhood programs; describes the nature of clay and presents a working vocabulary. Suggests methods of working with clay, including introducing clay to children, discovering its uses, clean up, firing clay, and finishing baked clay. Includes activity suggestions and…

  3. Sagittal laser optical tomography for imaging of rheumatoid finger joints.

    PubMed

    Hielscher, Andreas H; Klose, Alexander D; Scheel, Alexander K; Moa-Anderson, Bryte; Backhaus, Marina; Netz, Uwe; Beuthan, Jürgen

    2004-04-07

    We present a novel optical tomographic imaging system that was designed to determine two-dimensional spatial distribution of optical properties in a sagittal plane through finger joints. The system incorporates a single laser diode and a single silicon photodetector into a scanning device that records spatially resolved light intensities as they are transmitted through a finger. These data are input to a model-based iterative image reconstruction (MOBIIR) scheme, which uses the equation of radiative transfer (ERT) as a forward model for light propagation through tissue. We have used this system to obtain tomographic images of six proximal interphalangeal finger joints from two patients with rheumatoid arthritis. The optical images were compared to clinical symptoms and ultrasound images.

  4. Segregation induced fingering instabilities in granular avalanches

    NASA Astrophysics Data System (ADS)

    Woodhouse, Mark; Thornton, Anthony; Johnson, Chris; Kokelaar, Pete; Gray, Nico

    2013-04-01

    It is important to be able to predict the distance to which a hazardous natural granular flows (e.g. snow slab avalanches, debris-flows and pyroclastic flows) might travel, as this information is vital for accurate assessment of the risks posed by such events. In the high solids fraction regions of these flows the large particles commonly segregate to the surface, where they are transported to the margins to form bouldery flow fronts. In many natural flows these bouldery margins experience a much greater frictional force, leading to frontal instabilities. These instabilities create levees that channelize the flow vastly increasing the run-out distance. A similar effect can be observed in dry granular experiments, which use a combination of small round and large rough particles. When this mixture is poured down an inclined plane, particle size segregation causes the large particles to accumulate near the margins. Being rougher, the large particles experience a greater friction force and this configuration (rougher material in front of smoother) can be unstable. The instability causes the uniform flow front to break up into a series of fingers. A recent model for particle size-segregation has been coupled to existing avalanche models through a particle concentration dependent friction law. In this talk numerical solutions of this coupled system are presented and compared to both large scale experiments carried out at the USGS flume and more controlled small scale laboratory experiments. The coupled depth-averaged model captures the accumulation of large particles at the flow front. We show this large particle accumulation at the head of the flow can lead to the break-up of the initially uniform front into a series of fingers. However, we are unable to obtain a fully grid-resolved numerical solution; the width of the fingers decreases as the grid is refined. By considering the linear stability of a steady, fully-developed, bidisperse granular layer it is shown that

  5. Viscous fingering of a draining suspension

    NASA Astrophysics Data System (ADS)

    Chen, Yun; Malambri, Frank; Lee, Sungyon

    2016-11-01

    The Saffman-Taylor viscous fingering arises when a viscous oil is withdrawn from a Hele-Shaw cell that is filled with a less viscous fluid. When particles are introduced into the draining fluid, new behaviors emerge, which are unobserved in the well-established pure oil case. We experimentally investigate the particle-modified inward fingering for varying particle concentrations. In particular, the fingering growth rate and number of fingers are experimentally quantified and are shown to be directly affected by the presence of particles. The physical mechanism of the particle-modified fingering is also discussed.

  6. Acrylic Finger Prosthesis: A Case Report

    PubMed Central

    Bandela, Vinod; M, Bharathi; S V, Giridhar Reddy

    2014-01-01

    Hands basic function is to grasp, hold and manipulate items. Hand gesture is perhaps the most blatant example of non-verbal communication. Finger and partial finger amputations are most frequently encountered forms of partial hand loss. Common causes are traumatic injuries, congenital absence or malformations present great clinical challenges. In addition to immediate loss of grasp strength, finger absence may cause marked psychological trauma. Individuals who desire finger replacement usually have high expectation for the appearance of prosthesis. This clinical report portrays simple method to retain acrylic finger prosthesis. PMID:25302271

  7. Impact of Finger Type in Fingerprint Authentication

    NASA Astrophysics Data System (ADS)

    Gafurov, Davrondzhon; Bours, Patrick; Yang, Bian; Busch, Christoph

    Nowadays fingerprint verification system is the most widespread and accepted biometric technology that explores various features of the human fingers for this purpose. In general, every normal person has 10 fingers with different size. Although it is claimed that recognition performance with little fingers can be less accurate compared to other finger types, to our best knowledge, this has not been investigated yet. This paper presents our study on the topic of influence of the finger type into fingerprint recognition performance. For analysis we employ two fingerprint verification software packages (one public and one commercial). We conduct test on GUC100 multi sensor fingerprint database which contains fingerprint images of all 10 fingers from 100 subjects. Our analysis indeed confirms that performance with small fingers is less accurate than performance with the others fingers of the hand. It also appears that best performance is being obtained with thumb or index fingers. For example, performance deterioration from the best finger (i.e. index or thumb) to the worst fingers (i.e. small ones) can be in the range of 184%-1352%.

  8. Torpor Patterns in Desert Hedgehogs (Paraechinus aethiopicus) Represent Another New Point along a Thermoregulatory Continuum.

    PubMed

    Boyles, Justin G; Bennett, Nigel C; Mohammed, Osama B; Alagaili, Abdulaziz N

    Documenting variation in thermoregulatory patterns across phylogenetically and geographically diverse taxa is key to understanding the evolution of endothermy and heterothermy in birds and mammals. We recorded body temperature (Tb) in free-ranging desert hedgehogs (Paraechinus aethiopicus) across three seasons in the deserts of Saudi Arabia. Modal Tb's (35°-36.5°C) were slightly below normal for mammals but still warmer than those of other hedgehogs. The single maximum Tb recorded was 39.2°C, which is cooler than maximum Tb's recorded in most desert mammals. Desert hedgehogs commonly used torpor during winter and spring but never during summer. Torpor bouts occurred frequently but irregularly, and most lasted less than 24 h. Unlike daily heterotherms, desert hedgehogs did occasionally remain torpid for more than 24 h, including one bout of 101 h. Body temperatures during torpor were often within 2°-3°C of ambient temperature; however, we never recorded repeated bouts of long, predictable torpor punctuated by brief arousal periods similar to those common among seasonal hibernators. Thus, desert hedgehogs can be included on the ever-growing list of species that display torpor patterns intermediate to traditionally defined hibernators and daily heterotherms. Extant hedgehogs are a recent radiation within an ancient family, and the intermediate thermoregulatory pattern displayed by desert hedgehogs is unlike the deeper and more regular torpor seen in other hedgehogs, suggesting that this may be a derived-as opposed to ancestral-trait in this subfamily. We suggest that this family (Erinaceidae) and order (Eulipotyphla) may be important for understanding the evolution of thermoregulatory patterns among Laurasiatheria and mammals in general.

  9. The effect of ageing and fitness on thermoregulatory response to high-intensity exercise.

    PubMed

    Best, S; Caillaud, C; Thompson, M

    2012-08-01

    There are conflicting reports as to whether ageing causes a decreased thermoregulatory response, or if observed differences in previous studies are related to maximal aerobic capacity or training status. This study hypothesized that thermoregulatory response to severe exercise-heat stress is maintained with ageing when both young and older subjects are well trained. Seven older highly trained (OHT = 51-63 years) cyclists were matched with two groups of young cyclists (19-35 years); one group matched for training status [young highly trained (YHT) participants, n = 7] and another for V ˙ O 2 max [young moderately trained (YMT), n = 7]. Each participant exercised at 70% V ˙ O 2 max in hot (35°C, 40% relative humidity) and thermoneutral (20°C, 40% relative humidity) conditions for 60 min. Final rectal temperature in the thermoneutral and heat (YHT = 39.13 ± 0.33°C, YMT = 39.11 ± 0.38°C, OHT = 39.11 ± 0.51°C) tests were similar between all three groups. %HR(max) (heat test: YHT = 92.5 ± 6.0%, YMT = 91.6 ± 4.4%, OHT = 88.6 ± 5.1%), skin temperature, and cutaneous vascular conductance during cycling in both environments were similar between groups. Lower sweat loss and evaporative heat loss in the heat test in the OHT and YMT groups when compared with the YHT group reflected lower metabolic heat production. The findings of the present study suggest that thermoregulatory response is maintained with age among highly trained subjects.

  10. Thermoregulatory responses of middle-aged and young men during dry-heat acclimation.

    PubMed

    Pandolf, K B; Cadarette, B S; Sawka, M N; Young, A J; Francesconi, R P; Gonzalez, R R

    1988-07-01

    Thermoregulatory responses during heat acclimation were compared between nine young (mean age 21.2 yr) and nine middle-aged men (mean age 46.4 yr) who were matched (P greater than 0.05) for body weight, surface area, surface area-to-weight ratio, percent body fat, and maximal aerobic power. After evaluation in a comfortable environment (22 degrees C, 50% relative humidity), the men were heat acclimated by treadmill walking (1.56 m/s, 5% grade) for two 50-min exercise bouts separated by 10 min of rest for 10 consecutive days in a hot dry (49 degrees C ambient temperature, 20% relative humidity) environment. During the first day of heat exposure performance time was 27 min longer (P less than 0.05) for the middle-aged men, whereas final rectal and skin temperatures and heart rate were lower, and final total body sweat loss was higher (P less than 0.05) compared with the young men. These thermoregulatory advantages for the middle-aged men persisted for the first few days of exercise-heat acclimation (P less than 0.05). After acclimation no thermoregulatory or performance time differences were observed between groups (P greater than 0.05). Sweating sensitivity, esophageal temperature at sweating onset, and the sweating onset time did not differ (P greater than 0.05) between groups either pre- or postacclimatization. Plasma osmolality and sodium concentration were slightly lower for the young men both pre- and postacclimatization; however, both groups had a similar percent change in plasma volume from rest to exercise during these tests.(ABSTRACT TRUNCATED AT 250 WORDS)

  11. Social defeat stress induces hyperthermia through activation of thermoregulatory sympathetic premotor neurons in the medullary raphe region.

    PubMed

    Lkhagvasuren, Battuvshin; Nakamura, Yoshiko; Oka, Takakazu; Sudo, Nobuyuki; Nakamura, Kazuhiro

    2011-11-01

    Psychological stress-induced hyperthermia is a fundamental autonomic response in mammals. However, the central circuitry underlying this stress response is poorly understood. Here, we sought to identify sympathetic premotor neurons that mediate a hyperthermic response to social defeat stress, a psychological stress model. Intruder rats that were defeated by a dominant resident conspecific exhibited a rapid increase in abdominal temperature by up to 2.0  °C. In these defeated rats, we found that expression of Fos, a marker of neuronal activation, was increased in the rostral medullary raphe region centered in the rostral raphe pallidus and adjacent raphe magnus nuclei. In this region, Fos expression was observed in a large population of neurons expressing vesicular glutamate transporter 3 (VGLUT3), which are known as sympathetic premotor neurons controlling non-shivering thermogenesis in brown adipose tissue (BAT) and thermoregulatory constriction of skin blood vessels, and also in a small population of tryptophan hydroxylase-positive serotonergic neurons. Intraperitoneal injection of diazepam, an anxiolytic agent, but not indomethacin, an antipyretic, significantly reduced both the stress-induced hyperthermia and Fos expression in these medullary raphe neuronal populations. Systemic blockade of β3 -adrenoreceptors, which are abundantly expressed in BAT, also attenuated the stress-induced hyperthermia. These results suggest that psychological stress signals activate VGLUT3-expressing medullary raphe sympathetic premotor neurons, which then drive hyperthermic effector responses including BAT thermogenesis through β(3) -adrenoreceptors.

  12. Heat storage in Asian elephants during submaximal exercise: behavioral regulation of thermoregulatory constraints on activity in endothermic gigantotherms.

    PubMed

    Rowe, M F; Bakken, G S; Ratliff, J J; Langman, V A

    2013-05-15

    Gigantic size presents both opportunities and challenges in thermoregulation. Allometric scaling relationships suggest that gigantic animals have difficulty dissipating metabolic heat. Large body size permits the maintenance of fairly constant core body temperatures in ectothermic animals by means of gigantothermy. Conversely, gigantothermy combined with endothermic metabolic rate and activity likely results in heat production rates that exceed heat loss rates. In tropical environments, it has been suggested that a substantial rate of heat storage might result in a potentially lethal rise in core body temperature in both elephants and endothermic dinosaurs. However, the behavioral choice of nocturnal activity might reduce heat storage. We sought to test the hypothesis that there is a functionally significant relationship between heat storage and locomotion in Asian elephants (Elephas maximus), and model the thermoregulatory constraints on activity in elephants and a similarly sized migratory dinosaur, Edmontosaurus. Pre- and post-exercise (N=37 trials) measurements of core body temperature and skin temperature, using thermography were made in two adult female Asian elephants at the Audubon Zoo in New Orleans, LA, USA. Over ambient air temperatures ranging from 8 to 34.5°C, when elephants exercised in full sun, ~56 to 100% of active metabolic heat production was stored in core body tissues. We estimate that during nocturnal activity, in the absence of solar radiation, between 5 and 64% of metabolic heat production would be stored in core tissues. Potentially lethal rates of heat storage in active elephants and Edmontosaurus could be behaviorally regulated by nocturnal activity.

  13. 50 years of computer simulation of the human thermoregulatory system.

    PubMed

    Hensley, Daniel W; Mark, Andrew E; Abella, Jayvee R; Netscher, George M; Wissler, Eugene H; Diller, Kenneth R

    2013-02-01

    This paper presents an updated and augmented version of the Wissler human thermoregulation model that has been developed continuously over the past 50 years. The existing Fortran code is translated into C with extensive embedded commentary. A graphical user interface (GUI) has been developed in Python to facilitate convenient user designation of input and output variables and formatting of data presentation. Use of the code with the GUI is described and demonstrated. New physiological elements were added to the model to represent the hands and feet, including the unique vascular structures adapted for heat transfer associated with glabrous skin. The heat transfer function and efficacy of glabrous skin is unique within the entire body based on the capacity for a very high rate of blood perfusion and the novel capability for dynamic regulation of blood flow. The model was applied to quantify the absolute and relative contributions of glabrous skin flow to thermoregulation for varying levels of blood perfusion. The model also was used to demonstrate how the unique features of glabrous skin blood flow may be recruited to implement thermal therapeutic procedures. We have developed proprietary methods to manipulate the control of glabrous skin blood flow in conjunction with therapeutic devices and simulated the effect of these methods with the model.

  14. Integration of tactile input across fingers in a patient with finger agnosia.

    PubMed

    Anema, Helen A; Overvliet, Krista E; Smeets, Jeroen B J; Brenner, Eli; Dijkerman, H Chris

    2011-01-01

    Finger agnosia has been described as an inability to explicitly individuate between the fingers, which is possibly due to fused neural representations of these fingers. Hence, are patients with finger agnosia unable to keep tactile information perceived over several fingers separate? Here, we tested a finger agnosic patient (GO) on two tasks that measured the ability to keep tactile information simultaneously perceived by individual fingers separate. In experiment 1 GO performed a haptic search task, in which a target (the absence of a protruded line) needed to be identified among distracters (protruded lines). The lines were presented simultaneously to the fingertips of both hands. Similarly to the controls, her reaction time decreased when her fingers were aligned as compared to when her fingers were stretched and in an unaligned position. This suggests that she can keep tactile input from different fingers separate. In experiment two, GO was required to judge the position of a target tactile stimulus to the index finger, relatively to a reference tactile stimulus to the middle finger, both in fingers uncrossed and crossed position. GO was able to indicate the relative position of the target stimulus as well as healthy controls, which indicates that she was able to keep tactile information perceived by two neighbouring fingers separate. Interestingly, GO performed better as compared to the healthy controls in the finger crossed condition. Together, these results suggest the GO is able to implicitly distinguish between tactile information perceived by multiple fingers. We therefore conclude that finger agnosia is not caused by minor disruptions of low-level somatosensory processing. These findings further underpin the idea of a selective impaired higher order body representation restricted to the fingers as underlying cause of finger agnosia.

  15. Control of thermal balance by a liquid circulating garment based on a mathematical representation of the human thermoregulatory system. Ph.D. Thesis - California Univ., Berkeley

    NASA Technical Reports Server (NTRS)

    Kuznetz, L. H.

    1976-01-01

    Test data and a mathematical model of the human thermoregulatory system were used to investigate control of thermal balance by means of a liquid circulating garment (LCG). The test data were derived from five series of experiments in which environmental and metabolic conditions were varied parametrically as a function of several independent variables, including LCG flowrate, LCG inlet temperature, net environmental heat exchange, surrounding gas ventilation rate, ambient pressure, metabolic rate, and subjective/obligatory cooling control. The resultant data were used to relate skin temperature to LCG water temperature and flowrate, to assess a thermal comfort band, to demonstrate the relationship between metabolic rate and LCG heat dissipation, and so forth. The usefulness of the mathematical model as a tool for data interpretation and for generation of trends and relationships among the various physiological parameters was also investigated and verified.

  16. Comparison of viscous fingering patterns in polymer and newtonian solutions

    NASA Astrophysics Data System (ADS)

    Kawaguchi, Masami; Makino, Kyoko; Kato, Tadaya

    1997-02-01

    Viscous fingering patterns of aqueous glycerol and hydroxypropyl methyl cellulose (HPMC) solutions pushed by air in the Hele-Shaw cell were observed as a function of isopropyl alcohol. An increase in isopropyl alcohol led to a decrease in surface tension as well as an increase in viscosity of the respective solutions. For the glycerol solutions, namely Newtonian fluids, only the tip splitting pattern was observed, where the fingers were indeed narrower and the number of the fingers increased with increasing isopropyl alcohol content. These morphological changes in the patterns for the glycerol solutions were in agreement with the computer simulations based on the diffusion limited aggregation model. The finger tip velocity is proportional to the ratio of the injection pressure to viscosity according to Darcy's law prediction. In contrast, for HPMC solutions, which show shear-thinning, highly branched pattern only appeared when the injection pressure was changed. When isopropyl alcohol was added to HPMC solutions, a morphological transition from highly branched pattern to tip splitting one was observed. The transition in the pattern would be related to changes in both elastic properties and surface tension. The finger tip velocity of HPMC solutions is scaled with 1.5 power of the ratio of injection pressure to viscosity.

  17. Alternating zinc fingers in the human male associated protein ZFY: 2D NMR structure of an even finger and implications for jumping-linker DNA recognition

    SciTech Connect

    Kochoyan, M.; Havel, T.F.; Dahl, C.E. ); Nguyen, D.T.; Keutmann, H.T. ); Weiss, M.A. Massachusetts General Hospital, Boston )

    1991-04-09

    ZFY, a sex-related Zn-finger protein encoded by the human Y chromosome, is distinguished from the general class of Zn-finger proteins by the presence of a two-finger repeat. Whereas odd-numbered domains and linkers fit a general consensus, even-numbered domains and linkers exhibit systematic differences. Because this alternation may have fundamental implications for the mechanism of protein-DNA recognition, the authors have undertaken biochemical and structural studies of fragments of ZFY. They describe here the solution structure of a representative nonconsensus (even-numbered) Zn finger based on 2D NMR studies of a 30-residue peptide. Structural modeling by distance geometry and simulated annealing (DG/SA) demonstrates that this peptide folds as a miniglobular domain containing a C-terminal {beta}-hairpin and N-terminal {alpha}-helix ({beta}{beta}{alpha} motif). These features are similar to (but not identical with) those previously described in consensus-type Zn fingers (derived from ADR1 and Xfin); the similarities suggest that even and odd ZFY domains bind DNA by a common mechanism. A model of the protein-DNA complex (designated the jumping-linker model) is presented and discussed in terms of the ZFY two-finger repeat. In this model every other linker is proposed to cross the minor groove by means of a putative finger/linker submotif HX{sub 4}HX{sub 3}-hydrophobic residue-X{sub 3}.

  18. Prediction of Antichollintergic Drug Response Using a Thermoregulatory Exchange Index

    DTIC Science & Technology

    2000-01-01

    M.A. Kolka/ Journal of Thermal Biology 25 (2000) 157-163 One contributor to the decreased homeostatic com- pensation in such individuals chronically...response) and obesity . When chal- lenged exogenously by environmental heat stress, or endogenously via fever or exercise, a person’s facility to maintain...occur which would offset any imbalances in evaporative heat loss (Kolka et al., 1994). Some evidence using an ani- mal model indicates that preoptic

  19. Structure based design of protein linkers for zinc finger nuclease.

    PubMed

    Anand, Priya; Schug, Alexander; Wenzel, Wolfgang

    2013-10-01

    Zinc finger nucleases are a promising tool to edit DNA in many biological applications, in particular for gene knockout. Despite many efforts the number of genes that can be effectively targeted with ZFNs remains severely limited, as available constructs cannot address arbitrary gene sequences. Here, we develop a novel concept to significantly enhance the number of DNA sequences that can be targeted by ZFN. Using an efficient computational model, we provide an extensive library of possible linker molecules between individual zinc finger motifs in the construct that can skip up to 10 base pairs between adjacent zinc finger recognition sites in the DNA sequence, which increases the number of genes that can be efficiently targeted by more than an order of magnitude.

  20. Viscous fingering in an elastic channel

    NASA Astrophysics Data System (ADS)

    Hazel, Andrew L.; Ducloué, Lucie; Juel, Anne

    2016-11-01

    We investigate experimentally the fingering instability of a flat, steadily propagating interface in a Hele-Shaw channel, where the top boundary has been replaced by an elastic membrane. In order to create a steadily propagating flat front, we exploit the reopening modes of fluid-filled elasto-rigid channels. The collapsed upper boundary reopens through the steady propagation of a wide finger, when air is injected from one end at a constant flow rate. For high levels of collapse and high finger speed, the tip of the finger becomes flat, creating a leading edge normal to the direction of propagation, which in turn is subject to a smaller scale viscous fingering instability. By modifying the cross-sectional geometry of the channel, we can actuate the finger shape to observe a variety of small-scale fingering phenomena including growth in a direction normal to the propagation and dendrite formation. The instability of the flat front exhibits constant-length fingers, very similar to the stubby fingers observed in radial compliant Hele-Shaw cells, and reminiscent of the printer's instability travel with the front. We investigate the geometry of those fingers in terms of the speed of the front, and the geometry of the reopening region. The financial support of the Leverhulme Trust is gratefully acknowledged.

  1. Attenuated thermoregulatory responses with increased plasma osmolality in obese subjects during two seasons

    NASA Astrophysics Data System (ADS)

    Kanikowska, Dominika; Sato, Maki; Sugenoya, Junichi; Shimizu, Yuuki; Nishimura, Naoki; Inukai, Yoko; Iwase, Satoshi

    2013-09-01

    Obese subjects may be more vulnerable to injury from heat stress, and appear to be less efficient at thermoregulation. Sweat rate, tympanic temperature and osmolality in obese subjects were investigated in Japan during two seasons. The purpose of this study was to examine the relationship between obesity, thermoregulatory response and season. Five obese (BMI, 32.0 ± 4.9 kg/m2) and five non-obese (BMI, 23.2 ± 2.9 kg/m2) men participated in this experiment at latitude 35°10' N and longitude 136°57.9'E. The average atmospheric temperature was 29.1 ± 1.0 °C in summer and 3.3 ± 1.4 °C in winter. Tympanic temperature and sweat rate were measured during leg water immersion at 42 °C for 30 min. Blood samples were analyzed for plasma osmolality. The relationship between tympanic temperature and sweat rate decreased significantly in obese compared to in non-obese subjects in both seasons, there being a lowered sweat rate for any core temperature in obese subjects. Plasma osmolality was significantly higher in obese than in non-obese subjects in both seasons. Thermal sensation increased significantly in non-obese than in obese in winter but not in summer. Our data show that thermoregulatory responses are attenuated in obese subjects compared with controls, suggesting that obese people are at increased risk of heat-related illnesses.

  2. Thermoregulatory effects of caffeine ingestion during rest and exercise in men

    NASA Technical Reports Server (NTRS)

    Dunagan, Nancy; Greenleaf, John E.; Cisar, Craig J.

    1994-01-01

    Body temperatures and thermoregulatory responses were measured at rest and during submaximal exercise under normal ambient conditions in 11 aerobically-conditioned men (age = 29.2 +/- 6.2 yr, VO2(max) = 3.73 +/- 0.46 min(sup -1), relative body fat = 12.3 +/- 3.7 percent, mean +/- SD) with (CT) and without (NCT) the ingestion of 10 mg of caffeine per kg of body weight. Oxygen uptake (VO2), heart rate (HR), and rectal (T(sub re)) and mean skin (T-bar(sub sk)) temperatures were recorded for 100 minutes starting one minute after ingestion of caffeine or a placebo. Data were collected throughout 30 minutes of rest (sitting) and the following 70 minutes of sitting leg ergometer exercise using the same constant load (1,088 +/- 153 kgm/min) in both NCT and CT. The load resulted in a mean relative exercise intensity equal to approximately 68 percent of VO2(sub max). Skin heat conductance (H(sub sk)) and sweat rate were calculated. Two-way analysis of covariance revealed no significant (P greater than 0.05) differences between NCT and CT in VO2, HR, T(sub re), T-bar(sub sk), or H(sub sk). A dependent t-test indicated no significant difference between NCT and CT in sweat rate. Thus, a high level of caffeine ingestion has no detrimental effects on body temperatures and thermoregulatory responses during moderately heavy exercise in normal ambient conditions.

  3. The relative influences of exercise and coat-type on the thermoregulatory responses of cattle

    NASA Astrophysics Data System (ADS)

    Vajrabukka, C.; Thwaites, C. J.

    1984-03-01

    Field and climatic chamber studies revealed that walking at 4.5 km/h elicited greater thermoregulatory responses in Hereford cattle than did the possession of a wooly hair coat. Under mild field conditions, walking caused sweating rate to increase to 150 200 g/m2/h within one hour (P<0.001); no significant differences were recorded between wooly-coated and clipped cattle. Walking at 4.5 km/h on a treadmill in a climate chamber at 38°C and 34 mm Hg water vapour pressure elevated rectal (P<0.001) and skin (P<0.05) temperatures to levels considerably above those in stationary controls. There were no differential effects on sweating or respiratory rates, though the latter were generally higher in the exercising group. Differences in skin temperature, sweating and respiratory rates between coat-types and exercise groups in the climate chamber were similar, but exercise resulted in a much greater rectal temperature response. Overall, exercise represented a more potent thermoregulatory stimulus than a wooly hair coat.

  4. Thermoregulatory consequences of resonant microwave exposure. Final report, August 1987-December 1989

    SciTech Connect

    Adair, E.R.

    1990-06-01

    Four experiments were conducted in which it was shown that behavioral and autonomic thermo-regulatory responses are mobilized in an orderly fashion when squirrel monkeys undergo whole-body exposure at the resonant frequency, 450 MHz. The threshold for alteration of thermo-regulatory behavior is about 3 mW/sq cm, equivalent to an SAR of nearly 2 W/kg. Behavioral responses serve to regulate the skin temperature at the normally preferred level. Because of the deep penetration of the radiation at resonance, this regulation results in a stable hyperthermic offset or bias in the deep body temperature. This situation is identical to that which occurs during exercise. Although not yet studied, we presume that the magnitude of this offset will be a direct function of the energy deposited in the body or SAR. Autonomic response of peripheral vasodilation and sweating, manifested on the skin surface. are stimulated at SARs similar to the behavioral threshold, indicating the possibility that such responses could serve as auxiliary sensory cues to behavior.

  5. Thermoregulatory capacities and torpor in the South American marsupial, Dromiciops gliroides.

    PubMed

    Cortés, Pablo A; Franco, Marcela; Moreno-Gómez, Felipe N; Barrientos, Karin; Nespolo, Roberto F

    2014-10-01

    During periods of adverse conditions small endotherms depend on a continuous supply of food and energy to maintain body temperature. Thus, rapid and reversible phenotypic modifications at different organizational levels are key for an efficient use of resources and survival. In this study, we provide a quantitative description of thermoregulatory capacities and energy-saving strategies in the Chilean marsupial Dromiciops gliroides. In particular, we evaluated the effect of thermal acclimation on basal metabolic rate (BMR), thermal conductance (C) and torpor patterns, as well as the presence of non-shivering thermogenesis (NST) as a rewarming mechanism in this marsupial. Non-significant effects of thermal acclimation were observed in BMR, C and body mass, but cold-acclimated individuals exhibited significantly longer torpor bouts. Also, minimum body temperature during torpor, inter-bout body temperature and arousal rewarming rate were lower in cold-acclimated animals. Furthermore, we found that D. gliroides did not display NST in response to Norepinephrine. Hence, despite the high regulation of torpor of other species, D. gliroides shows low flexibility in the ability to adjust energy expenditure and insulation properties, and (as in other marsupials) NST do not seems to be important as thermoregulatory mechanism.

  6. Visual information without thermal energy may induce thermoregulatory-like cardiovascular responses

    PubMed Central

    2013-01-01

    Background Human core body temperature is kept quasi-constant regardless of varying thermal environments. It is well known that physiological thermoregulatory systems are under the control of central and peripheral sensory organs that are sensitive to thermal energy. If these systems wrongly respond to non-thermal stimuli, it may disturb human homeostasis. Methods Fifteen participants viewed video images evoking hot or cold impressions in a thermally constant environment. Cardiovascular indices were recorded during the experiments. Correlations between the ‘hot-cold’ impression scores and cardiovascular indices were calculated. Results The changes of heart rate, cardiac output, and total peripheral resistance were significantly correlated with the ‘hot-cold’ impression scores, and the tendencies were similar to those in actual thermal environments corresponding to the impressions. Conclusions The present results suggest that visual information without any thermal energy can affect physiological thermoregulatory systems at least superficially. To avoid such ‘virtual’ environments disturbing human homeostasis, further study and more attention are needed. PMID:24373765

  7. Effects of epinephrine on thermoregulatory behavior in lean and obese Zucker rats in the cold.

    PubMed

    Carlisle, H J; Dubuc, P U; Stock, M J

    1995-01-01

    This series of experiments examined whether epinephrine (EPI) produces the same thermoregulatory effects in the cold that have been reported for norepinephrine and isoproterenol. Lean and obese Zucker rats were trained to press a lever to activate infrared heat lamps in a cold (-8 degrees C) environment. Operant thermoregulatory behavior increased dose-dependently following EPI (0-100 micrograms/kg), but posttest colonic temperature (Tc) fell. Thermal balance calculations showed a substantial increase in net heat loss, more so in obese than lean animals. EPI is therefore thermolytic--i.e., disrupts thermal balance. A low dose (100 micrograms/kg) of the alpha-antagonist phentolamine produced a marked improvement in operant behavior, Tc, and thermal balance, whereas a comparable dose of the beta-antagonist propranolol had no beneficial effect. Increasing the dose of phentolamine worsened the responses with respect to the 100-micrograms/kg dose. The selective alpha 1-antagonist prazosin ameliorated the decrease in Tc induced by EPI but had little effect on operant behavior or thermal balance; the selective alpha 2-antagonist yohimbine had no effect on any parameter compared to EPI alone. These results suggest that the paradoxical effects of EPI in the cold are mediated by alpha-adrenoceptors, but definitive identification of the subclass of receptor involved cannot be determined.

  8. The direction dependence of thermoregulatory vasoconstriction during isoflurane/epidural anesthesia in humans.

    PubMed

    Ozaki, M; Sessler, D I; McGuire, J; Blanchard, D; Schroeder, M; Moayeri, A

    1993-10-01

    We tested the hypothesis that once thermoregulatory vasoconstriction is triggered at a given core temperature during isoflurane anesthesia, redilation starts at a substantially higher core temperature. To avoid direct perception of cutaneous cooling and warming, we used epidural anesthesia and limited our thermal manipulations to the blocked area. Seven volunteers were anesthetized with isoflurane/epidural anesthesia (approximately T9 dermatomal level). Core hypothermia was induced by surface cooling restricted to the legs. Cooling was continued until fingertip blood flow suddenly decreased (vasoconstriction threshold). The core was then rewarmed by heating the legs until fingertip flow suddenly increased toward initial values (redilation threshold). The difference between the two thresholds defined the direction-dependent hysteresis. Vasoconstriction occurred at 35.2 +/- 0.6 degrees C and vasodilation at 36.2 +/- 0.5 degrees C (P < 0.01, paired t-test); consequently, the hysteresis was 1.0 +/- 0.6 degrees C. The observed hysteresis suggests that thermoregulatory responses during combined isoflurane/epidural anesthesia are not determined simply by instantaneous thermal input to central controllers, but may also depend on the direction of core temperature change.

  9. Effects of hyperoxia on thermoregulatory responses during feet immersion to hot water in humans.

    PubMed

    Yamashita, Kazuaki; Tochihara, Yutaka

    2003-07-01

    This study examined effects of hyperoxia on thermoregulatory responses. Eight healthy male students (23.5+/-1.8 yrs) were involved in this study. They immersed their legs in a hot water bath (42 degrees C) for 60 minutes in a climate chamber. The conditions of oxygen concentration of a chamber were set at 21% (control), 25% (25%O(2)), and 30% (30%O(2)). Ambient temperature and relative humidity was maintained at 25 degrees C and 50% in every condition, respectively. Measurements included rectal temperature (Tre), skin temperature at 7 sites, laser Doppler flowmeter (LDF) on the back and forearm as an index of skin blood flow, heart rate, local sweat rate (Msw) on the back and forearm, and total body weight loss (BWL). Increases of Tre at 25%O(2) and 30%O(2) tended to be lower during the immersion than in the control. Mean skin temperature (Tsk) of the control increased gradually after the onset of sweating, while the Tsks at 25%O(2) and 30%O(2) maintained a constant level during sweating. LDFs on the forearm at 25%O(2) and 30%O(2) showed lower increases compared with the control. No significant differences in Msw on the back and the forearm and BWL were seen among the conditions. These results suggested that hyperoxia could not affect sweating responses but elicit an inhibitory effect on thermoregulatory skin blood flow.

  10. Control of dissected leaf morphology by a Cys(2)His(2) zinc finger transcription factor in the model legume Medicago truncatula

    PubMed Central

    Yu, Jianbin; Ge, Liangfa; Wang, Hongliang; Berbel, Ana; Liu, Yu; Chen, Yuhui; Li, Guangming; Tadege, Million; Wen, Jiangqi; Cosson, Viviane; Mysore, Kirankumar S.; Ratet, Pascal; Madueño, Francisco; Bai, Guihua; Chen, Rujin

    2010-01-01

    Plant leaves are diverse in their morphology, reflecting to a large degree the plant diversity in the natural environment. How different leaf morphology is determined is not yet understood. The leguminous plant Medicago truncatula exhibits dissected leaves with three leaflets at the tip. We show that development of the trifoliate leaves is determined by the Cys(2)His(2) zinc finger transcription factor PALM1. Loss-of-function mutants of PALM1 develop dissected leaves with five leaflets clustered at the tip. We demonstrate that PALM1 binds a specific promoter sequence and down-regulates the expression of the M. truncatula LEAFY/UNIFOLIATA orthologue SINGLE LEAFLET1 (SGL1), encoding an indeterminacy factor necessary for leaflet initiation. Our data indicate that SGL1 is required for leaflet proliferation in the palm1 mutant. Interestingly, ectopic expression of PALM1 effectively suppresses the lobed leaf phenotype from overexpression of a class 1 KNOTTED1-like homeobox protein in Arabidopsis plants. Taken together, our results show that PALM1 acts as a determinacy factor, regulates the spatial-temporal expression of SGL1 during leaf morphogenesis and together with the LEAFY/UNIFOLIATA orthologue plays an important role in orchestrating the compound leaf morphology in M. truncatula. PMID:20498057

  11. Moving Fingers under a Stick: A Laboratory Activity

    ERIC Educational Resources Information Center

    Massalha, Taha; Lanir, Yuval; Gluck, Paul

    2011-01-01

    We consider a demonstration in which pupils alternately slide and stop their fingers under a long horizontal rod which they support. The changeover is described in terms of the relevant kinetic and static friction. We present a model calculation, performed on a spreadsheet, which clarifies the process and describes graphically the stepwise…

  12. Moving Fingers under a Stick: A Laboratory Activity

    ERIC Educational Resources Information Center

    Massalha, Taha; Lanir, Yuval; Gluck, Paul

    2011-01-01

    We consider a demonstration in which pupils alternately slide and stop their fingers under a long horizontal rod which they support. The changeover is described in terms of the relevant kinetic and static friction. We present a model calculation, performed on a spreadsheet, which clarifies the process and describes graphically the stepwise…

  13. Heat transfer in fish: are short excursions between habitats a thermoregulatory behaviour to exploit resources in an unfavourable thermal environment?

    PubMed

    Pépino, Marc; Goyer, Katerine; Magnan, Pierre

    2015-11-01

    Temperature is the primary environmental factor affecting physiological processes in ectotherms. Heat-transfer models describe how the fish's internal temperature responds to a fluctuating thermal environment. Specifically, the rate coefficient (k), defined as the instantaneous rate of change in body temperature in relation to the difference between ambient and body temperature, summarizes the combined effects of direct thermal conduction through body mass, passive convection (intracellular and intercellular fluids) and forced convective heat transfer (cardiovascular system). The k-coefficient is widely used in fish ecology to understand how body temperature responds to changes in water temperature. The main objective of this study was to estimate the k-coefficient of brook charr equipped with internal temperature-sensitive transmitters in controlled laboratory experiments. Fish were first transferred from acclimation tanks (10°C) to tanks at 14, 19 or 23°C (warming experiments) and were then returned to the acclimation tanks (10°C; cooling experiments), thus producing six step changes in ambient temperature. We used non-linear mixed models to estimate the k-coefficient. Model comparisons indicated that the model incorporating the k-coefficient as a function of absolute temperature difference (dT: 4, 9 and 13°C) best described body temperature change. By simulating body temperature in a heterogeneous thermal environment, we provide theoretical predictions of maximum excursion duration between feeding and resting areas. Our simulations suggest that short (i.e. <60 min) excursions could be a common thermoregulatory behaviour adopted by cold freshwater fish species to sustain body temperature below a critical temperature threshold, enabling them to exploit resources in an unfavourable thermal environment. © 2015. Published by The Company of Biologists Ltd.

  14. Hemodynamic and thermoregulatory responses to lower body water immersion.

    PubMed

    Muller, Matthew D; Kim, Cihul-Ho; Seo, Yongsuk; Ryan, Edward J; Glickman, Ellen L

    2012-10-01

    Lower body water immersion (LBWI) is experienced in the marine industry but the physiological responses to LBWI are unclear. The purpose of the current experiment was to test the effects of water temperature and immersion duration on rectal temperature, heart rate, stroke volume, blood pressure, metabolic rate, and thermal sensation in healthy subjects. Nine young men underwent two 60-min trials of seated LBWI to the iliac crest in a counterbalanced fashion. On one occasion, the water was 35 degrees C (LBWI-Neutral) and on the other it was 13 degrees C (LBWI-Cold); the upper body remained thermoneutral and dry throughout. As expected, exposure to cold water reduced mean skin temperature and individuals reported cold thermal sensation. Mean arterial pressure was significantly higher at 60 min of LBWI-Cold (86 +/- 7 mmHg) compared to LBWI-Neutral (76 +/- 5 mmHg) while heart rate tended to be lower. The change in rectal temperature from baseline to 30 min of LBWI-Cold (delta = -0.01 +/- 0.21degrees C) was significantly smaller than the change in T(re) from 30 to 60 min of LBWI-Cold (delta = -0.46 +/- 0.16 degrees C). Despite this accelerated drop in core temperature during minutes 30-60, metabolic rate did not increase significantly. LBWI-Cold reduces core temperature and increases arterial blood pressure via an increase in total peripheral resistance. This experimental model may help scientists better understand the body during cold stress. Further, people who are occupationally exposed to cold water (when the torso, hands, and arms remain thermoneutral) may be at increased risk for hypothermia.

  15. Current status of ultrasonography of the finger

    PubMed Central

    2016-01-01

    The recent development of advanced high-resolution transducers has enabled the fast, easy, and dynamic ultrasonographic evaluation of small, superficial structures such as the finger. In order to best exploit these advances, it is important to understand the normal anatomy and the basic pathologies of the finger, as exemplified by the following conditions involving the dorsal, volar, and lateral sections of the finger: sagittal band injuries, mallet finger, and Boutonnière deformity (dorsal aspect); flexor tendon tears, trigger finger, and volar plate injuries (volar aspect); gamekeeper’s thumb (Stener lesions) and other collateral ligament tears (lateral aspect); and other lesions. This review provides a basis for understanding the ultrasonography of the finger and will therefore be useful for radiologists. PMID:26753604

  16. Finger-Jointed Wood Products.

    DTIC Science & Technology

    1981-04-01

    long enough to be useful (14, 36, 38, 59, 124). Nonstructural finger joints are primarily found in molding stock, trim, siding, fascia boards, door...all beams but two in series 7 and 8 to the grain. The average modulus of be slightly higher than that for apparently was related to the joints, rupture ...inch, and a tip thickness of combinations laminated by the plant . (a)A bolt hole on tensile strength 0.031 inch. The other was classified Straight-bevel

  17. Prosthetic Hand With Two Gripping Fingers

    NASA Technical Reports Server (NTRS)

    Norton, William E.; Belcher, Jewell B.; Vest, Thomas W.; Carden, James R.

    1993-01-01

    Prosthetic hand developed for amputee who retains significant portion of forearm. Outer end of device is end effector including two fingers, one moved by rotating remaining part of forearm about its longitudinal axis. Main body of end effector is end member supporting fingers, roller bearing assembly, and rack-and-pinion mechanism. Advantage of rack-and-pinion mechanism enables user to open or close gap between fingers with precision and force.

  18. Prosthetic Hand With Two Gripping Fingers

    NASA Technical Reports Server (NTRS)

    Norton, William E.; Belcher, Jewell B.; Vest, Thomas W.; Carden, James R.

    1993-01-01

    Prosthetic hand developed for amputee who retains significant portion of forearm. Outer end of device is end effector including two fingers, one moved by rotating remaining part of forearm about its longitudinal axis. Main body of end effector is end member supporting fingers, roller bearing assembly, and rack-and-pinion mechanism. Advantage of rack-and-pinion mechanism enables user to open or close gap between fingers with precision and force.

  19. Pediatric finger fractures: which ones turn ugly?

    PubMed

    Cornwall, Roger

    2012-06-01

    The majority of pediatric finger fractures can be treated by closed means with expected excellent outcomes. However, a subset of fractures can turn "ugly," with complications such as growth arrest, malunion, and joint dysfunction if not recognized and treated appropriately. The present paper discusses several fractures in a child's fingers that can cause substantial problems if not recognized promptly, highlighting important themes in the evaluation and treatment of a child's injured finger.

  20. Thermoregulatory changes anticipate hibernation onset by 45 days: data from free-living arctic ground squirrels.

    PubMed

    Sheriff, Michael J; Williams, Cory T; Kenagy, G J; Buck, C Loren; Barnes, Brian M

    2012-08-01

    Hibernation is a strategy of reducing energy expenditure, body temperature (T(b)) and activity used by endotherms to escape unpredictable or seasonally reduced food availability. Despite extensive research on thermoregulatory adjustments during hibernation, less is known about transitions in thermoregulatory state, particularly under natural conditions. Laboratory studies on hibernating ground squirrels have demonstrated that thermoregulatory adjustments may occur over short intervals when animals undergo several brief, preliminary torpor bouts prior to entering multiday torpor. These short torpor bouts have been suggested to reflect a resetting of hypothalamic regions that control T(b) or to precondition animals before they undergo deep, multiday torpor. Here, we examined continuous records of T(b) in 240 arctic ground squirrels (Urocitellus parryii) prior to hibernation in the wild and in captivity. In free-living squirrels, T(b) began to decline 45 days prior to hibernation, and average T(b) had decreased 4.28 °C at the onset of torpor. Further, we found that 75 % of free-living squirrels and 35 % of captive squirrels entered bouts of multiday torpor with a single T(b) decline and without previously showing short preliminary bouts. This study provides evidence that adjustments in the thermoregulatory component of hibernation begin far earlier than previously demonstrated. The gradual reduction in T(b) is likely a component of the suite of metabolic and behavioral adjustments, controlled by an endogenous, circannual rhythm, that vary seasonally in hibernating ground squirrels.

  1. Acute Physiological and Thermoregulatory Responses to Extended Interval Training in Endurance Runners: Influence of Athletic Performance and Age

    PubMed Central

    García-Pinillos, Felipe; Soto-Hermoso, Víctor Manuel; Latorre-Román, Pedro Ángel

    2015-01-01

    This study aimed to describe the acute impact of extended interval training (EIT) on physiological and thermoregulatory levels, as well as to determine the influence of athletic performance and age effect on the aforementioned response in endurance runners. Thirty-one experienced recreational male endurance runners voluntarily participated in this study. Subjects performed EIT on an outdoor running track, which consisted of 12 runs of 400 m. The rate of perceived exertion, physiological response through the peak and recovery heart rate, blood lactate, and thermoregulatory response through tympanic temperature, were controlled. A repeated measures analysis revealed significant differences throughout EIT in examined variables. Cluster analysis grouped according to the average performance in 400 m runs led to distinguish between athletes with a higher and lower sports level. Cluster analysis was also performed according to age, obtaining an older group and a younger group. The one-way analysis of variance between groups revealed no significant differences (p≥0.05) in the response to EIT. The results provide a detailed description of physiological and thermoregulatory responses to EIT in experienced endurance runners. This allows a better understanding of the impact of a common training stimulus on the physiological level inducing greater accuracy in the training prescription. Moreover, despite the differences in athletic performance or age, the acute physiological and thermoregulatory responses in endurance runners were similar, as long as EIT was performed at similar relative intensity. PMID:26839621

  2. EFFECTS OF ACUTE EXPOSURE TO CONCENTRATED AMBIENT PARTICULATES ON CARDIOPULMONARY, THERMOREGULATORY, AND BIOCHEMICAL PARAMETERS IN OLD SPONTANEOUSLY HYPERTENSIVE RATS

    EPA Science Inventory


    EFFECTS OF ACUTE EXPOSURE TO CONCENTRATED AMBIENT PARTICULATES ON CARDIOPULMONARY, THERMOREGULATORY, AND BIOCHEMICAL PARAMETERS IN OLD SPONTANEOUSLY HYPERTENSIVE RATS. JP Nolan1, LB Wichers2, DW Winsett1, UP Kodavanti1, MCJ Schladweiler1, DL Costa1, and WP Watkinson1. 1US E...

  3. EFFECTS OF INSTILLATION OF RESIDUAL OIL FLY ASH (ROFA) ON CARDIAC, PULMONARY, AND THERMOREGULATORY PARAMETERS IN SPONTANEOUSLY HYPERTENSIVE (SH) RATS

    EPA Science Inventory


    EFFECTS OF INSTILLATION OF RESIDUAL OIL FLY ASH (ROFA) ON CARDIAC, PULMONARY, AND THERMOREGULATORY PARAMETERS IN SPONTANEOUSLY HYPERTENSIVE (SH) RATS. LB Wichers1, JP Nolan2, DW Winsett2, AD Ledbetter2, UP Kodavanti2, MCJ Schladweiler2, R Hauser3, DC Christiani3, DL Costa2, ...

  4. EFFECTS OF INHALATION OF SOLUBLE METALLIC CONSTITUENTS OF PARTICULATE MATTER ON CARDIOPULMONARY, THERMOREGULATORY, AND BIOCHEMICAL PARAMETERS IN GUINEA PIGS

    EPA Science Inventory

    EFFECTS OF INHALATION OF SOLUBLE METALLIC CONSTITUENTS OF PARTICULATE MATTER ON CARDIOPULMONARY, THERMOREGULATORY, AND BIOCHEMICAL PARAMETERS IN GUINEA PIGS. JP Nolan1, LB Wichers2, J Stanek3, UP Kodavanti1, MCJ Schladweiler1, PA Evansky1, ER Lappi1, DL Costa1, and WP Watkinson1...

  5. Susceptibility of the aging Brown Norway rat to carbaryl, an anti-cholinesterase-based insecticide: Thermoregulatory and cardiovascular responses.

    EPA Science Inventory

    The proportion of aged in the United States is projected to expand markedly for the next several decades. Hence, the U.S.EPA is assessing if the aged are more susceptible to environmental toxicants. The thermoregulatory and cardiovascular responses of young adult, mature adult, a...

  6. EFFECTS OF INSTILLATION OF RESIDUAL OIL FLY ASH (ROFA) ON CARDIAC, PULMONARY, AND THERMOREGULATORY PARAMETERS IN SPONTANEOUSLY HYPERTENSIVE (SH) RATS

    EPA Science Inventory


    EFFECTS OF INSTILLATION OF RESIDUAL OIL FLY ASH (ROFA) ON CARDIAC, PULMONARY, AND THERMOREGULATORY PARAMETERS IN SPONTANEOUSLY HYPERTENSIVE (SH) RATS. LB Wichers1, JP Nolan2, DW Winsett2, AD Ledbetter2, UP Kodavanti2, MCJ Schladweiler2, R Hauser3, DC Christiani3, DL Costa2, ...

  7. EFFECTS OF INDUCED RESPIRATORY CHANGES ON CARDIAC, VENTILATORY, AND THERMOREGULATORY PARAMETERS IN HEALTHY SPRAGUE-DAWLEY RATS

    EPA Science Inventory


    EFFECTS OF INDUCED RESPIRATORY CHANGES ON CARDIAC, VENTILATORY, AND THERMOREGULATORY PARAMETERS IN HEALTHY SPRAGUE-DAWLEY RATS. LB Wichers1, WH Rowan2, DL Costa2, MJ Campen3 and WP Watkinson2 1UNC SPH, Chapel Hill, NC, USA; 2USEPA, ORD/NHEERL/ETD/PTB, RTP, NC, USA; 3LRRI, A...

  8. EFFECTS OF INSTILLATION OF RESIDUAL OIL FLY ASH ON INDICES OF CARDIAC, PULMONARY, AND THERMOREGULATORY FUNCTION IN SPONTANEOUSLY HYPERTENSIVE RATS

    EPA Science Inventory


    EFFECTS OF INSTILLED RESIDUAL OIL FLY ASH (ROFA) ON INDICES OF CARDIAC, PULMONARY, AND THERMOREGULATORY FUNCTION IN SPONTANEOUSLY HYPERTENSIVE (SH) RATS. LB Wichers1, JP Nolan2, UP Kodavanti2, MCJ Schladweiler2, R Hauser3, DW Winsett2, DL Costa2, and WP Watkinson2. 1UNC Sch...

  9. EFFECTS OF INDUCED RESPIRATORY CHANGES ON CARDIAC, VENTILATORY, AND THERMOREGULATORY PARAMETERS IN HEALTHY SPRAGUE-DAWLEY RATS

    EPA Science Inventory


    EFFECTS OF INDUCED RESPIRATORY CHANGES ON CARDIAC, VENTILATORY, AND THERMOREGULATORY PARAMETERS IN HEALTHY SPRAGUE-DAWLEY RATS. LB Wichers1, WH Rowan2, DL Costa2, MJ Campen3 and WP Watkinson2 1UNC SPH, Chapel Hill, NC, USA; 2USEPA, ORD/NHEERL/ETD/PTB, RTP, NC, USA; 3LRRI, A...

  10. EFFECTS OF INSTILLATION OF RESIDUAL OIL FLY ASH ON INDICES OF CARDIAC, PULMONARY, AND THERMOREGULATORY FUNCTION IN SPONTANEOUSLY HYPERTENSIVE RATS

    EPA Science Inventory


    EFFECTS OF INSTILLED RESIDUAL OIL FLY ASH (ROFA) ON INDICES OF CARDIAC, PULMONARY, AND THERMOREGULATORY FUNCTION IN SPONTANEOUSLY HYPERTENSIVE (SH) RATS. LB Wichers1, JP Nolan2, UP Kodavanti2, MCJ Schladweiler2, R Hauser3, DW Winsett2, DL Costa2, and WP Watkinson2. 1UNC Sch...

  11. EFFECTS OF ACUTE EXPOSURE TO CONCENTRATED AMBIENT PARTICULATES ON CARDIOPULMONARY, THERMOREGULATORY, AND BIOCHEMICAL PARAMETERS IN OLD SPONTANEOUSLY HYPERTENSIVE RATS

    EPA Science Inventory


    EFFECTS OF ACUTE EXPOSURE TO CONCENTRATED AMBIENT PARTICULATES ON CARDIOPULMONARY, THERMOREGULATORY, AND BIOCHEMICAL PARAMETERS IN OLD SPONTANEOUSLY HYPERTENSIVE RATS. JP Nolan1, LB Wichers2, DW Winsett1, UP Kodavanti1, MCJ Schladweiler1, DL Costa1, and WP Watkinson1. 1US E...

  12. EFFECTS OF INHALATION OF SOLUBLE METALLIC CONSTITUENTS OF PARTICULATE MATTER ON CARDIOPULMONARY, THERMOREGULATORY, AND BIOCHEMICAL PARAMETERS IN GUINEA PIGS

    EPA Science Inventory

    EFFECTS OF INHALATION OF SOLUBLE METALLIC CONSTITUENTS OF PARTICULATE MATTER ON CARDIOPULMONARY, THERMOREGULATORY, AND BIOCHEMICAL PARAMETERS IN GUINEA PIGS. JP Nolan1, LB Wichers2, J Stanek3, UP Kodavanti1, MCJ Schladweiler1, PA Evansky1, ER Lappi1, DL Costa1, and WP Watkinson1...

  13. Susceptibility of the aging Brown Norway rat to carbaryl, an anti-cholinesterase-based insecticide: Thermoregulatory and cardiovascular responses.

    EPA Science Inventory

    The proportion of aged in the United States is projected to expand markedly for the next several decades. Hence, the U.S.EPA is assessing if the aged are more susceptible to environmental toxicants. The thermoregulatory and cardiovascular responses of young adult, mature adult, a...

  14. A multiscale approach to simulating the conformational properties of unbound multi-C₂H₂ zinc finger proteins.

    PubMed

    Liu, Lei; Wade, Rebecca C; Heermann, Dieter W

    2015-09-01

    The conformational properties of unbound multi-Cys2 His2 (mC2H2) zinc finger proteins, in which zinc finger domains are connected by flexible linkers, are studied by a multiscale approach. Three methods on different length scales are utilized. First, atomic detail molecular dynamics simulations of one zinc finger and its adjacent flexible linker confirmed that the zinc finger is more rigid than the flexible linker. Second, the end-to-end distance distributions of mC2H2 zinc finger proteins are computed using an efficient atomistic pivoting algorithm, which only takes excluded volume interactions into consideration. The end-to-end distance distribution gradually changes its profile, from left-tailed to right-tailed, as the number of zinc fingers increases. This is explained by using a worm-like chain model. For proteins of a few zinc fingers, an effective bending constraint favors an extended conformation. Only for proteins containing more than nine zinc fingers, is a somewhat compacted conformation preferred. Third, a mesoscale model is modified to study both the local and the global conformational properties of multi-C2H2 zinc finger proteins. Simulations of the CCCTC-binding factor (CTCF), an important mC2H2 zinc finger protein for genome spatial organization, are presented. © 2015 Wiley Periodicals, Inc.

  15. Simulation of light transport in arthritic- and non-arthritic human fingers

    NASA Astrophysics Data System (ADS)

    Milanic, Matija; Paluchowski, Lukasz A.; Randeberg, Lise L.

    2014-03-01

    Rheumatoid arthritis is a disease that frequently leads to joint destruction. It has high incidence rates worldwide, and the disease significantly reduces patient's quality of life due to pain, swelling and stiffness of the affected joints. Early diagnosis is necessary to improve course of the disease, therefore sensitive and accurate diagnostic tools are required. Optical imaging techniques have capability for early diagnosis and monitoring of arthritis. As compared to conventional diagnostic techniques optical technique is a noninvasive, noncontact and fast way of collecting diagnostic information. However, a realistic model of light transport in human joints is needed for understanding and developing of such optical diagnostic tools. The aim of this study is to develop a 3D numerical model of light transport in a human finger. The model will guide development of a hyperspectral imaging (HSI) diagnostic modality for arthritis in human fingers. The implemented human finger geometry is based on anatomical data. Optical data of finger tissues are adjusted to represent either an arthritic or an unaffected finger. The geometry and optical data serve as input into a 3D Monte Carlo method, which calculate diffuse reflectance, transmittance and absorbed energy distributions. The parameters of the model are optimized based on HIS-measurements of human fingers. The presented model serves as an important tool for understanding and development of HSI as an arthritis diagnostic modality. Yet, it can be applied to other optical techniques and finger diseases.

  16. Thermoregulatory responses during prolonged upper-body exercise in cool and warm conditions.

    PubMed

    Price, M J; Campbell, I G

    2002-07-01

    The thermoregulatory responses of upper-body trained athletes were examined at rest, during prolonged arm crank exercise and recovery in cool (21.5 +/- 0.9 degrees C, 43.9 +/- 10.1% relative humidity; mean +/- s) and warm (31.5 +/- 0.6 degrees C, 48.9 +/- 8.4% relative humidity) conditions. Aural temperature increased from rest by 0.7 +/- 0.7 degrees C (P< 0.05) during exercise in cool conditions and by 1.6 +/- 0.7 degrees C during exercise in warm conditions (P< 0.05). During exercise in cool conditions, calf skin temperature decreased (1.5 +/- 1.3 degrees C), whereas an increase was observed during exercise in warm conditions (3.0 +/- 1.7 degrees C). Lower-body skin temperatures tended to increase by greater amounts than upper-body skin temperatures during exercise in warm conditions. No differences were observed in blood lactate, heart rate or respiratory exchange ratio responses between conditions. Perceived exertion at 45 min of exercise was greater than that reported at 5 min of exercise during the cool trial (P< 0.05), whereas during exercise in the warm trial the rating of perceived exertion increased from initial values by 30 min (P < 0.05). Heat storage, body mass losses and fluid consumption were greater during exercise in warm conditions (7.06 +/- 2.25 J x g(-1) x degrees C(-1), 1.3 +/- 0.5 kg and 1,038 +/- 356 ml, respectively) than in cool conditions (1.35 +/- 0.23 J x g(-1) x degrees C(-1), 0.8 +/- 0.2 kg and 530 +/- 284 ml, respectively; P < 0.05). The results of this study indicate that the increasing thermal strain with constant thermal stress in warm conditions is due to heat storage within the lower body. These results may aid in understanding thermoregulatory control mechanisms of populations with a thermoregulatory dysfunction, such as those with spinal cord injuries.

  17. Neural network committees for finger joint angle estimation from surface EMG signals

    PubMed Central

    Shrirao, Nikhil A; Reddy, Narender P; Kosuri, Durga R

    2009-01-01

    Background In virtual reality (VR) systems, the user's finger and hand positions are sensed and used to control the virtual environments. Direct biocontrol of VR environments using surface electromyography (SEMG) signals may be more synergistic and unconstraining to the user. The purpose of the present investigation was to develop a technique to predict the finger joint angle from the surface EMG measurements of the extensor muscle using neural network models. Methodology SEMG together with the actual joint angle measurements were obtained while the subject was performing flexion-extension rotation of the index finger at three speeds. Several neural networks were trained to predict the joint angle from the parameters extracted from the SEMG signals. The best networks were selected to form six committees. The neural network committees were evaluated using data from new subjects. Results There was hysteresis in the measured SMEG signals during the flexion-extension cycle. However, neural network committees were able to predict the joint angle with reasonable accuracy. RMS errors ranged from 0.085 ± 0.036 for fast speed finger-extension to 0.147 ± 0.026 for slow speed finger extension, and from 0.098 ± 0.023 for the fast speed finger flexion to 0.163 ± 0.054 for slow speed finger flexion. Conclusion Although hysteresis was observed in the measured SEMG signals, the committees of neural networks were able to predict the finger joint angle from SEMG signals. PMID:19154615

  18. Surface Tension and Fingering of Miscible Interfaces

    NASA Technical Reports Server (NTRS)

    Abib, Mohammed; Liu, Jian-Bang; Ronney, Paul D.

    1999-01-01

    Experiments on miscible, buoyantly unstable reaction-diffusion fronts and non-reacting displacement fronts in Hele-Shaw cells show a fingering-type instability whose wavelengths (lambda*) are consistent with an interfacial tension (sigma) at the front caused by the change in chemical composition, even though the solutions are miscible in all proportions. In conjunction with the Saffman-Taylor model, the relation sigma = K/tau, where tau is the interface thickness and K approximately equal 4 +/- 2 x 10(exp -6) dyne, enables prediction of our measured values of lambda* as well as results from prior experiments on miscible interfaces. These results indicate that even for miscible fluids, surface tension is generally a more significant factor than diffusion in interfacial stability and flow characteristics.

  19. Error compensation during finger force production after oneand four-finger voluntarily fatiguing exercise

    PubMed Central

    Kruger, Eric S.; Hoopes, Josh A.; Cordial, Rory J.; Li, Sheng

    2010-01-01

    The effect of muscle fatigue on error compensation strategies during multi-finger ramp force production tasks was investigated. Thirteen young, healthy subjects were instructed to produce a total force with four fingers of the right hand to accurately match a visually displayed template. The template consisted of a 3-s waiting period, a 3-s ramp force production (from 0 to 30% maximal voluntary contraction, MVC), and a 3-s constant force production. A series of twelve ramp trials was performed before and after fatigue. Fatigue was induced by a 60-s maximal isometric force production with either the index finger only or with all four fingers during two separate testing sessions. The average percent of drop was 38.2% in the MVC of the index finger after index-finger fatiguing exercise and 38.3% in the MVC of all fingers after four-finger fatiguing exercise. The ability of individual fingers to compensate for each other's errors in order for the total force to match the preset template was quantified as the error compensation index (ECI), i.e. the ratio of the sum of variances of individual finger forces and the variance of the total force. By comparing pre- and post-fatigue performance during four-finger ramp force production, we observed that the variance of the total force was not significantly changed after one- or four-finger fatiguing exercise. The ECI significantly decreased after four-finger fatiguing exercise, especially during the last second of the ramp; while the ECI remained unchanged after index finger single-finger fatiguing exercise. These results suggest that the central nervous system is able to utilize the abundant degrees of freedom to compensate for partial impairment of the motor apparatus induced by muscle fatigue to maintain the desired performance. However, this ability is significantly decreased when all elements of the motor apparatus are impaired. PMID:17443316

  20. Creating Number Semantics through Finger Movement Perception

    ERIC Educational Resources Information Center

    Badets, Arnaud; Pesenti, Mauro

    2010-01-01

    Communication, language and conceptual knowledge related to concrete objects may rely on the sensory-motor systems from which they emerge. How abstract concepts can emerge from these systems is however still unknown. Here we report a functional interaction between a specific meaningful finger movement, such as a finger grip closing, and a concept…

  1. Correcting Finger Counting to Snellen Acuity.

    PubMed

    Karanjia, Rustum; Hwang, Tiffany Jean; Chen, Alexander Francis; Pouw, Andrew; Tian, Jack J; Chu, Edward R; Wang, Michelle Y; Tran, Jeffrey Show; Sadun, Alfredo A

    2016-10-01

    In this paper, the authors describe an online tool with which to convert and thus quantify count finger measurements of visual acuity into Snellen equivalents. It is hoped that this tool allows for the re-interpretation of retrospectively collected data that provide visual acuity in terms of qualitative count finger measurements.

  2. Correcting Finger Counting to Snellen Acuity

    PubMed Central

    Karanjia, Rustum; Hwang, Tiffany Jean; Chen, Alexander Francis; Pouw, Andrew; Tian, Jack J.; Chu, Edward R.; Wang, Michelle Y.; Tran, Jeffrey Show; Sadun, Alfredo A.

    2016-01-01

    ABSTRACT In this paper, the authors describe an online tool with which to convert and thus quantify count finger measurements of visual acuity into Snellen equivalents. It is hoped that this tool allows for the re-interpretation of retrospectively collected data that provide visual acuity in terms of qualitative count finger measurements. PMID:27928408

  3. Finger Mathematics: A Method for All Children.

    ERIC Educational Resources Information Center

    Ogletree, Earl J.; Chavez, Maria

    The instruction of finger counting and finger calculation, also known as Chisanbop, is promoted as a natural method of introducing and teaching the basic processes of addition, subtraction, multiplication and division to children, particularly to those who are mentally and physically handicapped. The sequential process for teaching finger…

  4. Creating Number Semantics through Finger Movement Perception

    ERIC Educational Resources Information Center

    Badets, Arnaud; Pesenti, Mauro

    2010-01-01

    Communication, language and conceptual knowledge related to concrete objects may rely on the sensory-motor systems from which they emerge. How abstract concepts can emerge from these systems is however still unknown. Here we report a functional interaction between a specific meaningful finger movement, such as a finger grip closing, and a concept…

  5. Fixed and random effects in the variation of the finger ridge count: a study of fragile-X families.

    PubMed

    Loesch, D Z; Huggins, R M

    1992-05-01

    A maximum-likelihood scoring technique for analysis of pedigree data allows for the concurrent estimation of random and of fixed effects in a quantitative trait. We included both types of effects in genetic models, to study the sources of variation in finger ridge count in 54 large families affected with the fragile-X disorder. The fixed effects were represented by fragile X and sex, and the random effects by environmental and genetic variance. We found a significant effect of fragile X in the mean of the finger ridge count on the thumb (finger 1) and index finger (finger 2), which had the lowest heritability and a negligible nonadditive component of genetic variance. This was in contrast with ridge counts on fingers 3 and 4, which showed little fragile-X effect, but high heritability and a significant nonadditive component. A contrast in genetic properties for ridge counts on fingers 1 and 2, compared with these counts on the remaining three fingers, may be relevant to increased selection pressures on functions of the thumb and of the index finger in evolution of modern man. We have also demonstrated an important effect of fragile X in increasing the additive variance in covariance, especially between male pairs. These findings suggest that the effect of the fragile-X genotype in finger ridge count is additive and superimposed on the normal hereditary variations in this trait.

  6. Fixed and random effects in the variation of the finger ridge count: a study of fragile-X families.

    PubMed Central

    Loesch, D Z; Huggins, R M

    1992-01-01

    A maximum-likelihood scoring technique for analysis of pedigree data allows for the concurrent estimation of random and of fixed effects in a quantitative trait. We included both types of effects in genetic models, to study the sources of variation in finger ridge count in 54 large families affected with the fragile-X disorder. The fixed effects were represented by fragile X and sex, and the random effects by environmental and genetic variance. We found a significant effect of fragile X in the mean of the finger ridge count on the thumb (finger 1) and index finger (finger 2), which had the lowest heritability and a negligible nonadditive component of genetic variance. This was in contrast with ridge counts on fingers 3 and 4, which showed little fragile-X effect, but high heritability and a significant nonadditive component. A contrast in genetic properties for ridge counts on fingers 1 and 2, compared with these counts on the remaining three fingers, may be relevant to increased selection pressures on functions of the thumb and of the index finger in evolution of modern man. We have also demonstrated an important effect of fragile X in increasing the additive variance in covariance, especially between male pairs. These findings suggest that the effect of the fragile-X genotype in finger ridge count is additive and superimposed on the normal hereditary variations in this trait. PMID:1570836

  7. Real-time single-molecule studies of the motions of DNA polymerase fingers illuminate DNA synthesis mechanisms.

    PubMed

    Evans, Geraint W; Hohlbein, Johannes; Craggs, Timothy; Aigrain, Louise; Kapanidis, Achillefs N

    2015-07-13

    DNA polymerases maintain genomic integrity by copying DNA with high fidelity. A conformational change important for fidelity is the motion of the polymerase fingers subdomain from an open to a closed conformation upon binding of a complementary nucleotide. We previously employed intra-protein single-molecule FRET on diffusing molecules to observe fingers conformations in polymerase-DNA complexes. Here, we used the same FRET ruler on surface-immobilized complexes to observe fingers-opening and closing of individual polymerase molecules in real time. Our results revealed the presence of intrinsic dynamics in the binary complex, characterized by slow fingers-closing and fast fingers-opening. When binary complexes were incubated with increasing concentrations of complementary nucleotide, the fingers-closing rate increased, strongly supporting an induced-fit model for nucleotide recognition. Meanwhile, the opening rate in ternary complexes with complementary nucleotide was 6 s(-1), much slower than either fingers closing or the rate-limiting step in the forward direction; this rate balance ensures that, after nucleotide binding and fingers-closing, nucleotide incorporation is overwhelmingly likely to occur. Our results for ternary complexes with a non-complementary dNTP confirmed the presence of a state corresponding to partially closed fingers and suggested a radically different rate balance regarding fingers transitions, which allows polymerase to achieve high fidelity.

  8. Global analysis of Drosophila Cys₂-His₂ zinc finger proteins reveals a multitude of novel recognition motifs and binding determinants.

    PubMed

    Enuameh, Metewo Selase; Asriyan, Yuna; Richards, Adam; Christensen, Ryan G; Hall, Victoria L; Kazemian, Majid; Zhu, Cong; Pham, Hannah; Cheng, Qiong; Blatti, Charles; Brasefield, Jessie A; Basciotta, Matthew D; Ou, Jianhong; McNulty, Joseph C; Zhu, Lihua J; Celniker, Susan E; Sinha, Saurabh; Stormo, Gary D; Brodsky, Michael H; Wolfe, Scot A

    2013-06-01

    Cys2-His2 zinc finger proteins (ZFPs) are the largest group of transcription factors in higher metazoans. A complete characterization of these ZFPs and their associated target sequences is pivotal to fully annotate transcriptional regulatory networks in metazoan genomes. As a first step in this process, we have characterized the DNA-binding specificities of 129 zinc finger sets from Drosophila using a bacterial one-hybrid system. This data set contains the DNA-binding specificities for at least one encoded ZFP from 70 unique genes and 23 alternate splice isoforms representing the largest set of characterized ZFPs from any organism described to date. These recognition motifs can be used to predict genomic binding sites for these factors within the fruit fly genome. Subsets of fingers from these ZFPs were characterized to define their orientation and register on their recognition sequences, thereby allowing us to define the recognition diversity within this finger set. We find that the characterized fingers can specify 47 of the 64 possible DNA triplets. To confirm the utility of our finger recognition models, we employed subsets of Drosophila fingers in combination with an existing archive of artificial zinc finger modules to create ZFPs with novel DNA-binding specificity. These hybrids of natural and artificial fingers can be used to create functional zinc finger nucleases for editing vertebrate genomes.

  9. The Thermoregulatory Function of Thatched Nests in the South American Grass-Cutting Ant, Acromyrmex heyeri

    PubMed Central

    Bollazzi, Martin; Roces, Flavio

    2010-01-01

    The construction of mound-shaped nests by ants is considered as a behavioral adaptation to low environmental temperatures, i.e., colonies achieve higher and more stables temperatures than those of the environment. Besides the well-known nests of boreal Formica wood-ants, several species of South American leaf-cutting ants of the genus Acromyrmex construct thatched nests. Acromyrmex workers import plant fragments as building material, and arrange them so as to form a thatch covering a central chamber, where the fungus garden is located. Thus, the degree of thermoregulation attained by the fungus garden inside the thatched nest largely depends on how the thatch affects the thermal relations between the fungus and the environment. This work was aimed at studying the thermoregulatory function of the thatched nests built by the grass-cutting ant Acromyrmex heyeri Forel (Hymenoptera: Formicidae: Myrmicinae). Nest and environmental temperatures were measured as a function of solar radiation on the long-term. The thermal diffusivity of the nest thatch was measured and compared to that of the surrounding soil, in order to assess the influence of the building material on the nest's thermoregulatory ability. The results showed that the average core temperature of thatched nests was higher than that of the environment, but remained below values harmful for the fungus. This thermoregulation was brought about by the low thermal diffusivity of the nest thatch built by workers with plant fragments, instead of the readily-available soil particles that have a higher thermal diffusivity. The thatch prevented diurnal nest overheating by the incoming solar radiation, and avoided losses of the accumulated daily heat into the cold air during the night. The adaptive value of thatching behavior in Acromyrmex leaf-cutting ants occurring in the southernmost distribution range is discussed. PMID:20883129

  10. Attenuated thermoregulatory responses with increased plasma osmolality in obese subjects during two seasons.

    PubMed

    Kanikowska, Dominika; Sato, Maki; Sugenoya, Junichi; Shimizu, Yuuki; Nishimura, Naoki; Inukai, Yoko; Iwase, Satoshi

    2013-09-01

    Obese subjects may be more vulnerable to injury from heat stress, and appear to be less efficient at thermoregulation. Sweat rate, tympanic temperature and osmolality in obese subjects were investigated in Japan during two seasons. The purpose of this study was to examine the relationship between obesity, thermoregulatory response and season. Five obese (BMI, 32.0 ± 4.9 kg/m²) and five non-obese (BMI, 23.2 ± 2.9 kg/m²) men participated in this experiment at latitude 35°10' N and longitude 136°57.9'E. The average atmospheric temperature was 29.1 ± 1.0 °C in summer and 3.3 ± 1.4 °C in winter. Tympanic temperature and sweat rate were measured during leg water immersion at 42 °C for 30 min. Blood samples were analyzed for plasma osmolality. The relationship between tympanic temperature and sweat rate decreased significantly in obese compared to in non-obese subjects in both seasons, there being a lowered sweat rate for any core temperature in obese subjects. Plasma osmolality was significantly higher in obese than in non-obese subjects in both seasons. Thermal sensation increased significantly in non-obese than in obese in winter but not in summer. Our data show that thermoregulatory responses are attenuated in obese subjects compared with controls, suggesting that obese people are at increased risk of heat-related illnesses.

  11. Exercise tolerance and thermoregulatory responses during cycling in boys and men.

    PubMed

    Rowland, Thomas; Hagenbuch, Sean; Pober, David; Garrison, Anne

    2008-02-01

    Physiological responses to exercise in the heat differ between prepubertal children and young adults. Whether these maturity-related variations imply lower exercise tolerance, inferior thermoregulation, and greater risk for heat injury in the child is uncertain. This study directly compared thermoregulatory and cardiovascular responses as well as endurance performance between prepubertal boys and adult males during steady-load cycling in moderately hot and cool ambient conditions with moderate humidity. Eight prepubertal boys (age 11.7 +/- 0.4 yr) and eight adult men (age 31.8 +/- 2.0 yr) performed steady-load cycling to exhaustion at an intensity equivalent to approximately 65% peak V O2 in both hot (approximately 31 degrees C) and cool (approximately 19 degrees C) environments, with fluid intake ad libitum. Exercise duration in the heat was shorter for both groups (hot: men 30.46 +/- 8.84 min, boys 29.30 +/- 6.19 min; cold: men 42.88 +/- 11.79 min, boys 41.38 +/- 6.30 min), with no significant difference between men and boys (P > 0.05). Increases in rectal temperature, heart rate, and cardiac index were similar between groups and conditions. Stroke index, mean arterial pressure, and arterial venous oxygen difference were stable and similar in both conditions, without group differences. No significant dehydration was observed in men or boys. This study failed to reveal differences in exercise tolerance, thermoregulatory adaptation, or cardiovascular response to exercise in the heat between euhydrated prepubertal boys and adult men.

  12. The thermoregulatory function of thatched nests in the South American grass-cutting ant, Acromyrmex heyeri.

    PubMed

    Bollazzi, Martin; Roces, Flavio

    2010-01-01

    The construction of mound-shaped nests by ants is considered as a behavioral adaptation to low environmental temperatures, i.e., colonies achieve higher and more stables temperatures than those of the environment. Besides the well-known nests of boreal Formica wood-ants, several species of South American leaf-cutting ants of the genus Acromyrmex construct thatched nests. Acromyrmex workers import plant fragments as building material, and arrange them so as to form a thatch covering a central chamber, where the fungus garden is located. Thus, the degree of thermoregulation attained by the fungus garden inside the thatched nest largely depends on how the thatch affects the thermal relations between the fungus and the environment. This work was aimed at studying the thermoregulatory function of the thatched nests built by the grass-cutting ant Acromyrmex heyeri Forel (Hymenoptera: Formicidae: Myrmicinae). Nest and environmental temperatures were measured as a function of solar radiation on the long-term. The thermal diffusivity of the nest thatch was measured and compared to that of the surrounding soil, in order to assess the influence of the building material on the nest's thermoregulatory ability. The results showed that the average core temperature of thatched nests was higher than that of the environment, but remained below values harmful for the fungus. This thermoregulation was brought about by the low thermal diffusivity of the nest thatch built by workers with plant fragments, instead of the readily-available soil particles that have a higher thermal diffusivity. The thatch prevented diurnal nest overheating by the incoming solar radiation, and avoided losses of the accumulated daily heat into the cold air during the night. The adaptive value of thatching behavior in Acromyrmex leaf-cutting ants occurring in the southernmost distribution range is discussed.

  13. Attenuated thermoregulatory sweating and cutaneous vasodilation after 14-day bed rest in humans.

    PubMed

    Michikami, Daisaku; Kamiya, Atsunori; Fu, Qi; Iwase, Satoshi; Mano, Tadaaki; Sunagawa, Kenji

    2004-01-01

    We investigated the effect of head-down bed rest (HDBR) for 14 days on thermoregulatory sweating and cutaneous vasodilation in humans. Fluid intake was ad libitum during HDBR. We induced whole body heating by increasing skin temperature for 1 h with a water-perfused blanket through which hot water (42 degrees C) was circulated. The experimental room was air-conditioned (27 degrees C, 30-40% relative humidity). We measured skin blood flow (chest and forearm), skin temperatures (chest, upper arm, forearm, thigh, and calf), and tympanic temperature. We also measured sweat rate by the ventilated capsule method in which the skin area for measurement was drained by dry air conditioned at 27 degrees C under similar skin temperatures in both trials. We calculated cutaneous vascular conductance (CVC) from the ratio of skin blood flow to mean blood pressure. From tympanic temperature-sweat rate and -CVC relationships, we assessed the threshold temperature and sensitivity as the slope response of variables to a given change in tympanic temperature. HDBR increased the threshold temperature for sweating by 0.31 degrees C at the chest and 0.32 degrees C at the forearm, whereas it reduced sensitivity by 40% at the chest and 31% at the forearm. HDBR increased the threshold temperature for cutaneous vasodilation, whereas it decreased sensitivity. HDBR reduced plasma volume by 11%, whereas it did not change plasma osmolarity. The increase in the threshold temperature for sweating correlated with that for cutaneous vasodilation. In conclusion, HDBR attenuated thermoregulatory sweating and cutaneous vasodilation by increasing the threshold temperature and decreasing sensitivity. HDBR increased the threshold temperature for sweating and cutaneous vasodilation by similar magnitudes, whereas it decreased their sensitivity by different magnitudes.

  14. Time of feeding and possible associated thermoregulatory benefits in bronze mannikins Lonchura cucullata.

    PubMed

    Seagram, R; Adams, N; Slotow, R

    2001-11-01

    Birds with a small body size have a high surface area to volume ratio, and this means that they have a high rate of heat loss to the environment. Birds may employ behavioural strategies in order to counter this heat loss. The adjustment of feeding patterns in the short term is probably the least documented of all of these strategies. Feeding results in the specific dynamic effect (SDE) which increases the metabolic rate of animals after a feeding bout. This increase in metabolic rate has been reported to possibly substitute for thermoregulatory costs in a variety of endotherms, including house wrens (Troglodytes aedon) and a variety of finch species. The thermoneutral zone was described for bronze mannikins, Lonchura cucullata (T(lc)=33.7 degrees C), and the bronze mannikins' post-absorptive physiology was described within this thermoneutral zone. Bronze mannikin mean basal metabolic rate (0.043+/-0.0038 S.E. ml O(2) min(-1) g(-1)), daytime resting metabolic rates (0.0549+/-0.0088 S.E. ml O(2) min(-1) g(-1)), and diurnal metabolic responses were described. The SDE in bronze mannikins was demonstrated within the thermoneutral zone, and was quantified. The mean magnitude of the SDE was 26.42% of mean total metabolism of post-absorptive birds. The magnitude of this SDE was independent of meal size and bird body mass. Assuming a 100% substitution, the presence of the SDE may afford bronze mannikins a maximum thermoregulatory energy saving of approximately 71.76 J g(-1) over a 300-min period.

  15. A simple and valid method to determine thermoregulatory sweating threshold and sensitivity.

    PubMed

    Cheuvront, Samuel N; Bearden, Shawn E; Kenefick, Robert W; Ely, Brett R; Degroot, David W; Sawka, Michael N; Montain, Scott J

    2009-07-01

    Sweating threshold temperature and sweating sensitivity responses are measured to evaluate thermoregulatory control. However, analytic approaches vary, and no standardized methodology has been validated. This study validated a simple and standardized method, segmented linear regression (SReg), for determination of sweating threshold temperature and sensitivity. Archived data were extracted for analysis from studies in which local arm sweat rate (m(sw); ventilated dew-point temperature sensor) and esophageal temperature (T(es)) were measured under a variety of conditions. The relationship m(sw)/T(es) from 16 experiments was analyzed by seven experienced raters (Rater), using a variety of empirical methods, and compared against SReg for the determination of sweating threshold temperature and sweating sensitivity values. Individual interrater differences (n = 324 comparisons) and differences between Rater and SReg (n = 110 comparisons) were evaluated within the context of biologically important limits of magnitude (LOM) via a modified Bland-Altman approach. The average Rater and SReg outputs for threshold temperature and sensitivity were compared (n = 16) using inferential statistics. Rater employed a very diverse set of criteria to determine the sweating threshold temperature and sweating sensitivity for the 16 data sets, but interrater differences were within the LOM for 95% (threshold) and 73% (sensitivity) of observations, respectively. Differences between mean Rater and SReg were within the LOM 90% (threshold) and 83% (sensitivity) of the time, respectively. Rater and SReg were not different by conventional t-test (P > 0.05). SReg provides a simple, valid, and standardized way to determine sweating threshold temperature and sweating sensitivity values for thermoregulatory studies.

  16. Effects of creatine on thermoregulatory responses while exercising in the heat.

    PubMed

    Mendel, Ronald W; Blegen, Mark; Cheatham, Chris; Antonio, Jose; Ziegenfuss, Tim

    2005-03-01

    We hypothesized that creatine supplementation would interfere with normal body fluid shifts that occur during exercise in a hot environment due to its osmotic effect intracellularly. This study examined the effects of acute creatine loading (20 g/d for 5 d) on the thermoregulatory response of the body during a bout of exercise at 39 degrees C. Subjects (15 men and 1 woman) performed a cycle test of maximum oxygen consumption to determine the proper work rate for the heat-stress test (40 min at 55% maximum oxygen consumption at 39 degrees C) and were assigned to a creatine group (n = 8) or a placebo group (n = 8) in a double-blind fashion. Each group performed the heat-stress test on two separate occasions: before supplementation and after supplementation (20 g/d of creatine with Gatorade or Solka-floc plus Gatorade). Dependent variables included rectal temperature, mean skin temperature, mean body temperature, and perceived thermal sensation. Repeated measure analysis of variance showed a significant (P < or = 0.05) increase in body weight in the group supplemented with Gatorade. Core temperature was significantly lower after supplementation for both groups combined (before supplementation at 37.85 degrees C and after supplementation at 37.7 degrees C), with no difference between groups. A significant three-way interaction (group x trial x time) was also found for rectal temperature, with both groups having significantly lower rectal temperature after supplementation. Mean body and mean skin temperatures showed no differences. Short-term creatine supplementation (20 g/d for 5 d) did not have a negative effect on thermoregulatory responses during exercise at 39 degrees C.

  17. Generic Automated Multi-function Finger Design

    NASA Astrophysics Data System (ADS)

    Honarpardaz, M.; Tarkian, M.; Sirkett, D.; Ölvander, J.; Feng, X.; Elf, J.; Sjögren, R.

    2016-11-01

    Multi-function fingers that are able to handle multiple workpieces are crucial in improvement of a robot workcell. Design automation of multi-function fingers is highly demanded by robot industries to overcome the current iterative, time consuming and complex manual design process. However, the existing approaches for the multi-function finger design automation are unable to entirely meet the robot industries’ need. This paper proposes a generic approach for design automation of multi-function fingers. The proposed approach completely automates the design process and requires no expert skill. In addition, this approach executes the design process much faster than the current manual process. To validate the approach, multi-function fingers are successfully designed for two case studies. Further, the results are discussed and benchmarked with existing approaches.

  18. Elastic fingering patterns in confined lifting flows.

    PubMed

    Fontana, João V; Miranda, José A

    2016-09-01

    The elastic fingering phenomenon occurs when two confined fluids are brought into contact, and due to a chemical reaction, the interface separating them becomes elastic. We study elastic fingering pattern formation in Newtonian fluids flowing in a lifting (time-dependent gap) Hele-Shaw cell. Using a mode-coupling approach, nonlinear effects induced by the interplay between viscous and elastic forces are investigated and the weakly nonlinear behavior of the fluid-fluid interfacial patterns is analyzed. Our results indicate that the existence of the elastic interface allows the development of unexpected morphological behaviors in such Newtonian fluid flow systems. More specifically, we show that depending on the values of the governing physical parameters, the observed elastic fingering structures are characterized by the occurrence of either finger tip splitting or side branching. The impact of the elastic interface on finger-competition events is also discussed.

  19. Use of twin dorsal middle phalangeal finger flaps for thumb or index finger reconstruction.

    PubMed

    Qi, W; Chen, K J

    2013-05-01

    Amputation or degloving injuries of the thumb or index finger are highly disabling. We describe the use of twin dorsal middle finger flaps harvested from the dorsal aspects of the middle and ring fingers, and based on one palmar proper digital artery, its venae comitantes, and the dorsal branches of the palmar digital nerves of the middle and ring fingers, respectively. These flaps offer advantages when large soft tissue defects of the thumb or index finger are present. In this study, twin dorsal middle finger flaps were used in nine patients (six thumbs, three index fingers). All flaps completely survived. At the mean follow-up of 20 months, the appearance of the reconstructed thumbs or index fingers was acceptable, the length was maintained, and the mean static 2-point discrimination values were 10 mm in the palmar flap and 13 mm in the dorsal flap of the reconstructed digit. All patients were satisfied with the appearance and mobility of the donor fingers. All but one donor finger showed normal finger pulp sensibility, with a static 2-point discrimination between 3 and 6 mm.

  20. Elastic Suppression of Viscous Fingering

    NASA Astrophysics Data System (ADS)

    Peng, Gunnar; Lister, John

    2016-11-01

    Consider peeling an elastic tape or beam away from a rigid base to which it is stuck by a film of viscous liquid. The peeling motion requires air to invade the viscous liquid and is thus susceptible to the Saffman-Taylor fingering instability. We analyse the fundamental travelling-wave solution and show that the advancing air-liquid interface remains linearly stable at higher capillary numbers than in a standard Hele-Shaw cell. A short-wavelength expansion yields an analytical expression for the growth rate which is valid for all unstable modes throughout the parameter space, allowing us to identify and quantify four distinct physical mechanisms that each help suppress the instability. Applying our method to the experiments by Pihler-Puzovic et al. (2012) reveals that the radial geometry and time-variation stabilize the system further.

  1. Fingering instability of Bingham fluids

    NASA Astrophysics Data System (ADS)

    Ghadge, Shilpa; Myers, Tim

    2005-11-01

    Contact line instabilities have been extensively studied and many useful results obtained for industrial applications. Our research in this area is to explore these instabilities for non-Newtonian fluids which has wide scope in geological, biological as well as industrial areas. In this talk, we will present an analysis of fingering instability near a contact line of the thin sheet of fluid flowing down on a moderately inclined plane. This instability has been well studied for Newtonian fluids. We explore the effect of a yield strength of the fluid on this instability. We have conveniently assumed the presence of the precussor film of small thickness ahead of the fluid film to avoid some mathematical singularities. Using a lubrication-type approximation, we perform a linear stability analysis of a straight contact line. We will show comparison with some experimental results using suspensions of kaolin in silicone oil as a yield strength fluid.

  2. Finger tremor in Parkinson's disease.

    PubMed

    Lakie, M; Mutch, W J

    1989-03-01

    Finger tremor was investigated in 20 patients (age range 54-88 yr) diagnosed as suffering from idiopathic Parkinson's disease and six controls of a similar age and no known neurological abnormality. In nine of the patients tremor was not clinically obvious. When the tremor of these patients was recorded immediately after voluntary movement and subjected to instrumental analysis there were consistently observable differences from the controls. Such analysis may have diagnostic potential when there is clinical uncertainty. Surface EMG recordings were obtained from four patients. One patient had a large resting tremor with obvious reciprocating activity in flexors and extensors; in the others who had no symptomatic tremor there was reciprocating activity only after movement, and this died away in a few seconds as the induced tremor disappeared.

  3. Alpha trimmed correlation for touchless finger image mosaicing

    NASA Astrophysics Data System (ADS)

    Rao, Shishir P.; Rajendran, Rahul; Agaian, Sos S.; Mulawka, Marzena Mary Ann

    2016-05-01

    In this paper, a novel technique to mosaic multiview contactless finger images is presented. This technique makes use of different correlation methods, such as, the Alpha-trimmed correlation, Pearson's correlation [1], Kendall's correlation [2], and Spearman's correlation [2], to combine multiple views of the finger. The key contributions of the algorithm are: 1) stitches images more accurately, 2) provides better image fusion effects, 3) has better visual effect on the overall image, and 4) is more reliable. The extensive computer simulations show that the proposed method produces better or comparable stitched images than several state-of-the-art methods, such as those presented by Feng Liu [3], K Choi [4], H Choi [5], and G Parziale [6]. In addition, we also compare various correlation techniques with the correlation method mentioned in [3] and analyze the output. In the future, this method can be extended to obtain a 3D model of the finger using multiple views of the finger, and help in generating scenic panoramic images and underwater 360-degree panoramas.

  4. An effective preprocessing method for finger vein recognition

    NASA Astrophysics Data System (ADS)

    Peng, JiaLiang; Li, Qiong; Wang, Ning; Abd El-Latif, Ahmed A.; Niu, Xiamu

    2013-07-01

    The image preprocessing plays an important role in finger vein recognition system. However, previous preprocessing schemes remind weakness to be resolved for the high finger vein recongtion performance. In this paper, we propose a new finger vein preprocessing that includes finger region localization, alignment, finger vein ROI segmentation and enhancement. The experimental results show that the proposed scheme is capable of enhancing the quality of finger vein image effectively and reliably.

  5. Is the thumb a fifth finger? A study of digit interaction during force production tasks

    PubMed Central

    Olafsdottir, Halla; Zatsiorsky, Vladimir M.; Latash, Mark L.

    2010-01-01

    We studied indices of digit interaction in single- and multi-digit maximal voluntary contraction (MVC) tests when the thumb acted either in parallel or in opposition to the fingers. The peak force produced by the thumb was much higher when the thumb acted in opposition to the fingers and its share of the total force in the five-digit MVC test increased dramatically. The fingers showed relatively similar peak forces and unchanged sharing patterns in the four-finger MVC task when the thumb acted in parallel and in opposition to the fingers. Enslaving during one-digit tasks showed relatively mild differences between the two conditions, while the differences became large when enslaving was quantified for multi-digit tasks. Force deficit was pronounced when the thumb acted in parallel to the fingers; it showed a monotonic increase with the number of explicitly involved digits up to four digits and then a drop when all five digits were involved. Force deficit all but disappeared when the thumb acted in opposition to the fingers. However, for both thumb positions, indices of digit interaction were similar for groups of digits that did or did not include the thumb. These results suggest that, given a certain hand configuration, the central nervous system treats the thumb as a fifth finger. They provide strong support for the hypothesis that indices of digit interaction reflect neural factors, not the peripheral design of the hand. An earlier formal model was able to account for the data when the thumb acted in parallel to the fingers. However, it failed for the data with the thumb acting in opposition to the fingers. PMID:15322785

  6. Finger wear detection for production line battery tester

    DOEpatents

    Depiante, E.V.

    1997-11-18

    A method is described for detecting wear in a battery tester probe. The method includes providing a battery tester unit having at least one tester finger, generating a tester signal using the tester fingers and battery tester unit with the signal characteristic of the electrochemical condition of the battery and the tester finger, applying wavelet transformation to the tester signal including computing a mother wavelet to produce finger wear indicator signals, analyzing the signals to create a finger wear index, comparing the wear index for the tester finger with the index for a new tester finger and generating a tester finger signal change signal to indicate achieving a threshold wear change. 9 figs.

  7. Finger wear detection for production line battery tester

    DOEpatents

    Depiante, Eduardo V.

    1997-01-01

    A method for detecting wear in a battery tester probe. The method includes providing a battery tester unit having at least one tester finger, generating a tester signal using the tester fingers and battery tester unit with the signal characteristic of the electrochemical condition of the battery and the tester finger, applying wavelet transformation to the tester signal including computing a mother wavelet to produce finger wear indicator signals, analyzing the signals to create a finger wear index, comparing the wear index for the tester finger with the index for a new tester finger and generating a tester finger signal change signal to indicate achieving a threshold wear change.

  8. EFFECTS OF INHALATION OF METALLIC CONSTITUENTS OF PARTICULATE MATTER AIR POLLUTION ON CARDIOPULMONARY AND THERMOREGULATORY PARAMETERS IN HEALTH AND COMPROMISED RATS

    EPA Science Inventory


    EFFECTS OF INHALATION OF METALLIC CONSTITUENTS OF PARTICULATE MATTER AIR POLLUTION ON CARDIOPULMONARY AND THERMOREGULATORY PARAMETERS IN HEALTHY AND COMPROMISED RATS. Watkinson, WP, Campen, MJ, Wichers, LB, Nolan, JP, Kodavanti, UP, Schladweiler, MCJ, Evansky, PA, Lappi, ER,...

  9. EFFECTS OF INHALATION OF METALLIC CONSTITUENTS OF PARTICULATE MATTER AIR POLLUTION ON CARDIOPULMONARY AND THERMOREGULATORY PARAMETERS IN HEALTH AND COMPROMISED RATS

    EPA Science Inventory


    EFFECTS OF INHALATION OF METALLIC CONSTITUENTS OF PARTICULATE MATTER AIR POLLUTION ON CARDIOPULMONARY AND THERMOREGULATORY PARAMETERS IN HEALTHY AND COMPROMISED RATS. Watkinson, WP, Campen, MJ, Wichers, LB, Nolan, JP, Kodavanti, UP, Schladweiler, MCJ, Evansky, PA, Lappi, ER,...

  10. The effect of enslaving on perception of finger forces.

    PubMed

    Li, Sheng; Leonard, Charles T

    2006-07-01

    The primary purpose was to examine the effect of enslaving on finger force perception during isometric finger force production using an ipsilateral force-matching paradigm. Fourteen subjects were instructed to produce varying levels of reference forces [10, 20, 30, and 40% maximal voluntary contraction (MVC)] force using one finger (index, I or little, L) and to reproduce these forces using the same finger (homo-finger tasks, I/I and L/L) or a different finger (hetero-finger tasks, I/L and L/I). Forces of all fingers were recorded. During homo-finger tasks, no differences were found in force magnitude or relative level of force (expressed as a proportion of MVC). The index finger matching force magnitudes were greater than the little finger reference force magnitudes, with significantly lower levels of relative force during L/I tasks; while the little finger matching forces underestimated the index finger reference forces with significantly higher levels of relative force during I/L tasks. The difference in the matching and reference forces by the instructed finger(s), i.e., matching error, was larger in hetero-finger tasks than in homo-finger tasks, particularly at high reference force levels (30, 40% MVC). When forces of all fingers were considered, enslaving (uninstructed finger forces) significantly minimized matching errors of the total force during both I/L and L/I hetero-finger tasks, especially at high reference force levels. Our results show that there is a tendency to match the absolute magnitude of the total force during ipsilateral finger force-matching tasks. This tendency is likely related to enslaving effects. Our results provide evidence that all (instructed and uninstructed) finger forces are sensed, thus resulting in perception of the absolute magnitude of total finger force.

  11. Finger somatotopy in human motor cortex.

    PubMed

    Beisteiner, R; Windischberger, C; Lanzenberger, R; Edward, V; Cunnington, R; Erdler, M; Gartus, A; Streibl, B; Moser, E; Deecke, L

    2001-06-01

    Although qualitative reports about somatotopic representation of fingers in the human motor cortex exist, up to now no study could provide clear statistical evidence. The goal of the present study was to reinvestigate finger motor somatotopy by means of a thorough investigation of standardized movements of the index and little finger of the right hand. Using high resolution fMRI at 3 Tesla, blood oxygenation level-dependent (BOLD) responses in a group of 26 subjects were repeatedly measured to achieve reliable statistical results. The center of mass of all activated voxels within the primary motor cortex was calculated for each finger and each run. Results of all runs were averaged to yield an individual index and little finger representation for each subject. The mean center of mass localizations for all subjects were then submitted to a paired t test. Results show a highly significant though small scale somatotopy of fingerspecific activation patterns in the order indicated by Penfields motor homunculus. In addition, considerable overlap of finger specific BOLD responses was found. Comparing various methods of analysis, the mean center of mass distance for the two fingers was 2--3 mm with overlapping voxels included and 4--5 mm with overlapping voxels excluded. Our data may be best understood in the context of the work of Schieber (1999) who recently described overlapping somatotopic gradients in lesion studies with humans. Copyright 2001 Academic Press.

  12. Trigger finger, tendinosis, and intratendinous gene expression.

    PubMed

    Lundin, A-C; Aspenberg, P; Eliasson, P

    2014-04-01

    The pathogenesis of trigger finger has generally been ascribed to primary changes in the first annular ligament. In contrast, we recently found histological changes in the tendons, similar to the findings in Achilles tendinosis or tendinopathy. We therefore hypothesized that trigger finger tendons would show differences in gene expression in comparison to normal tendons in a pattern similar to what is published for Achilles tendinosis. We performed quantitative real-time polymerase chain reaction on biopsies from finger flexor tendons, 13 trigger fingers and 13 apparently healthy control tendons, to assess the expression of 10 genes which have been described to be differently expressed in tendinosis (collagen type 1a1, collagen 3a1, MMP-2, MMP-3, ADAMTS-5, TIMP-3, aggrecan, biglycan, decorin, and versican). In trigger finger tendons, collagen types 1a1 and 3a1, aggrecan and biglycan were all up-regulated, and MMP-3and TIMP-3 were down-regulated. These changes were statistically significant and have been previously described for Achilles tendinosis. The remaining four genes were not significantly altered. The changes in gene expression support the hypothesis that trigger finger is a form of tendinosis. Because trigger finger is a common condition, often treated surgically, it could provide opportunities for clinical research on tendinosis. © 2012 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  13. Stretch flow of confined non-Newtonian fluids: nonlinear fingering dynamics.

    PubMed

    Brandão, Rodolfo; Fontana, João V; Miranda, José A

    2013-12-01

    We employ a weakly nonlinear perturbative scheme to investigate the stretch flow of a non-Newtonian fluid confined in Hele-Shaw cell for which the upper plate is lifted. A generalized Darcy's law is utilized to model interfacial fingering formation in both the weak shear-thinning and weak shear-thickening limits. Within this context, we analyze how the interfacial finger shapes and the nonlinear competition dynamics among fingers are affected by the non-Newtonian nature of the stretched fluid.

  14. Optical flow based finger stroke detection

    NASA Astrophysics Data System (ADS)

    Zhu, Zhongdi; Li, Bin; Wang, Kongqiao

    2010-07-01

    Finger stroke detection is an important topic in hand based Human Computer Interaction (HCI) system. Few research studies have carried out effective solutions to this problem. In this paper, we present a novel approach for stroke detection based on mono vision. Via analyzing the optical flow field within the finger area, our method is able to detect finger stroke under various camera position and visual angles. We present a thorough evaluation for each component of the algorithm, and show its efficiency and effectiveness on solving difficult stroke detection problems.

  15. A Search for Plasma "Fingers" in the Io Torus

    NASA Astrophysics Data System (ADS)

    Jaggar, S.; Schneider, N. M.; Bagenal, F.; Trauger, J. T.

    1996-09-01

    We have compared model and data images of the Io plasma torus to test the radial diffusion model of Yang et al. (J. Geophys. Res., Vol 99, p. 8755, 1994). They predict that radial diffusion takes the form of `fingers' of dense plasma flowing outward due to the centrifugal force. Furthermore, they show that the spatial scale of these significant longitudinal variations is approximately 15(o) . The observations used in this study were obtained using a 2.4m telescope at Las Campanas Observatory using a narrowband filter to isolate emissions from S(++) at 9531 Angstroms. S(++) images are dominated by emission from the warm torus where outward radial transport is expected. Although S(+) images are brighter, they are contaminated by emission from the cold torus where fingers are not expected. We used the Colorado Io Torus Emission Package (CITEP)(Taylor et al., J. Geophys. Res., Vol. 100, p. 19541, 1995) to simulate images of the torus with fingers. CITEP is a comprehensive program which incorporates accurate atomic physics, plasma physics and magnetic field models to simulate the brightness and morphology or torus emissions. We used a Voyager empirical model (Bagenal, J. Geophys. Res., Vol. 99, p. 11043, 1994) modulated by a sinusoidal longitudinal density variation with a 15(o) period and an amplitude proportional to the density at that L-shell. We compared simulated images with data to determine the minimum density contrast necessary to make fingers detectable. We place an upper limit on the density contrast of +/- 20% on a 15(o) spatial scale. We conclude that either the density contrast of this mode of transport is small, or other processes are more important for radial transport. This constraint can also be used in other radial diffusion models which predict density variations on this spatial scale. This work has been supported by NASA's Planetary Astronomy and Planetary Atmospheres programs.

  16. Hydrodynamic analysis of different finger positions in swimming: a computational fluid dynamics approach.

    PubMed

    Vilas-Boas, João Paulo; Ramos, Rui J; Fernandes, Ricardo J; Silva, António J; Rouboa, Abel I; Machado, Leandro; Barbosa, Tiago M; Marinho, Daniel A

    2015-02-01

    The aim of this research was to numerically clarify the effect of finger spreading and thumb abduction on the hydrodynamic force generated by the hand and forearm during swimming. A computational fluid dynamics (CFD) analysis of a realistic hand and forearm model obtained using a computer tomography scanner was conducted. A mean flow speed of 2 m · s(-1) was used to analyze the possible combinations of three finger positions (grouped, partially spread, totally spread), three thumb positions (adducted, partially abducted, totally abducted), three angles of attack (a = 0°, 45°, 90°), and four sweepback angles (y = 0°, 90°, 180°, 270°) to yield a total of 108 simulated situations. The values of the drag coefficient were observed to increase with the angle of attack for all sweepback angles and finger and thumb positions. For y = 0° and 180°, the model with the thumb adducted and with the little finger spread presented higher drag coefficient values for a = 45° and 90°. Lift coefficient values were observed to be very low at a = 0° and 90° for all of the sweepback angles and finger and thumb positions studied, although very similar values are obtained at a = 45°. For y = 0° and 180°, the effect of finger and thumb positions appears to be much most distinct, indicating that having the thumb slightly abducted and the fingers grouped is a preferable position at y = 180°, whereas at y = 0°, having the thumb adducted and fingers slightly spread yielded higher lift values. Results show that finger and thumb positioning in swimming is a determinant of the propulsive force produced during swimming; indeed, this force is dependent on the direction of the flow over the hand and forearm, which changes across the arm's stroke.

  17. Numerical simulation of double-diffusive finger convection

    USGS Publications Warehouse

    Hughes, J.D.; Sanford, W.E.; Vacher, H.L.

    2005-01-01

    A hybrid finite element, integrated finite difference numerical model is developed for the simulation of double-diffusive and multicomponent flow in two and three dimensions. The model is based on a multidimensional, density-dependent, saturated-unsaturated transport model (SUTRA), which uses one governing equation for fluid flow and another for solute transport. The solute-transport equation is applied sequentially to each simulated species. Density coupling of the flow and solute-transport equations is accounted for and handled using a sequential implicit Picard iterative scheme. High-resolution data from a double-diffusive Hele-Shaw experiment, initially in a density-stable configuration, is used to verify the numerical model. The temporal and spatial evolution of simulated double-diffusive convection is in good agreement with experimental results. Numerical results are very sensitive to discretization and correspond closest to experimental results when element sizes adequately define the spatial resolution of observed fingering. Numerical results also indicate that differences in the molecular diffusivity of sodium chloride and the dye used to visualize experimental sodium chloride concentrations are significant and cause inaccurate mapping of sodium chloride concentrations by the dye, especially at late times. As a result of reduced diffusion, simulated dye fingers are better defined than simulated sodium chloride fingers and exhibit more vertical mass transfer. Copyright 2005 by the American Geophysical Union.

  18. Role of a decrease in body heat content in the thermoregulatory reaction of the concha auriculae vessels

    NASA Technical Reports Server (NTRS)

    Slepchuk, N. A.; Rumyantsev, G. V.

    1980-01-01

    At the constant ambient temperature 28-30 C the rabbit ear vessels were dilated and their temperature was 34.8/0.1 C. Administration of the 23-29 C water into the stomach entailed thermoregulatory construction of the ear vessels within 15-25 min. The response occurred at various combinations of temperature changes in different parts of the body. The heat content of the rabbit body, as calculated by the blood temperature in the aorta arc, reduced by 266.3 + or - 26.2 cal/kg at the beginning of the response. The decrease in the organism heat content seems to serve as a signal for occurrence of a corresponding thermoregulatory response.

  19. Aggregate Constraints for Virtual Manipulation with Soft Fingers.

    PubMed

    Talvas, Anthony; Marchal, Maud; Duriez, Christian; Otaduy, Miguel A

    2015-04-01

    Interactive dexterous manipulation of virtual objects remains a complex challenge that requires both appropriate hand models and accurate physically-based simulation of interactions. In this paper, we propose an approach based on novel aggregate constraints for simulating dexterous grasping using soft fingers. Our approach aims at improving the computation of contact mechanics when many contact points are involved, by aggregating the multiple contact constraints into a minimal set of constraints. We also introduce a method for non-uniform pressure distribution over the contact surface, to adapt the response when touching sharp edges. We use the Coulomb-Contensou friction model to efficiently simulate tangential and torsional friction. We show through different use cases that our aggregate constraint formulation is well-suited for simulating interactively dexterous manipulation of virtual objects through soft fingers, and efficiently reduces the computation time of constraint solving.

  20. The role of finger representations and saccades for number processing: an FMRI study in children.

    PubMed

    Krinzinger, Helga; Koten, Jan Willem; Horoufchin, Houpand; Kohn, Nils; Arndt, Dominique; Sahr, Katleen; Konrad, Kerstin; Willmes, Klaus

    2011-01-01

    A possible functional role of finger representations for the development of early numerical cognition has been the subject of recent debate; however, until now, only behavioral studies have directly supported this view. Working from recent models of number processing, we focused on the neural networks involved in numerical tasks and their relationship to the areas underlying finger representations and saccades in children aged 6-12 years. We were able to differentiate three parietal circuits that were related to distinct aspects of number processing. Abstract magnitude processing was subserved by an association area also activated by saccades and visually guided finger movements. Addition processes led to activation in an area only engaged during saccade encoding, whereas counting processes resulted in the activation of an area only activated during visually guided finger movements, namely in the anterior intraparietal sulcus. Apart from this area, a large network of specifically finger-related brain areas including the ventral precentral sulcus, supplementary motor area, dorso-lateral prefrontal cortex, insula, thalamus, midbrain, and cerebellum was activated during (particularly non-symbolic) exact addition but not during magnitude comparison. Moreover, a finger-related activation cluster in the right ventral precentral sulcus was only present during non-symbolic addition and magnitude comparison, but not during symbolic number processing tasks. We conclude that finger counting may critically mediate the step from non-symbolic to symbolic and exact number processing via somatosensory integration processes and therefore represents an important example of embodied cognition.

  1. Finger blood flow in Antarctica

    PubMed Central

    Elkington, E. J.

    1968-01-01

    1. Finger blood flow was estimated, by strain-gauge plethysmography, before and during a 1 hr immersion in ice water, on twenty-five men throughout a year at Wilkes, Antarctica. A total of 121 satisfactory immersions were made. 2. Blood flow before and during immersion decreased significantly in the colder months of the year, and the increase caused by cold-induced vasodilatation (CIVD) became less as the year progressed. The time of onset, blood flow at onset, and frequency of the cycles of CIVD showed no significant relation to the coldness of the weather (as measured by mean monthly wind chill) or the time in months. Comparisons of blood flow before and after five field trips (average duration 42 days), on which cold exposure was more severe than at Wilkes station, gave similar results. 3. The results suggest that vasoconstrictor tone increased. This interpretation agrees with previous work on general acclimatization in Antarctica, but contrasts with work elsewhere on local acclimatization of the hands. PMID:5684034

  2. Enhanced slow-wave EEG activity and thermoregulatory impairment following the inhibition of the lateral hypothalamus in the rat.

    PubMed

    Cerri, Matteo; Del Vecchio, Flavia; Mastrotto, Marco; Luppi, Marco; Martelli, Davide; Perez, Emanuele; Tupone, Domenico; Zamboni, Giovanni; Amici, Roberto

    2014-01-01

    Neurons within the lateral hypothalamus (LH) are thought to be able to evoke behavioural responses that are coordinated with an adequate level of autonomic activity. Recently, the acute pharmacological inhibition of LH has been shown to depress wakefulness and promote NREM sleep, while suppressing REM sleep. These effects have been suggested to be the consequence of the inhibition of specific neuronal populations within the LH, i.e. the orexin and the MCH neurons, respectively. However, the interpretation of these results is limited by the lack of quantitative analysis of the electroencephalographic (EEG) activity that is critical for the assessment of NREM sleep quality and the presence of aborted NREM-to-REM sleep transitions. Furthermore, the lack of evaluation of the autonomic and thermoregulatory effects of the treatment does not exclude the possibility that the wake-sleep changes are merely the consequence of the autonomic, in particular thermoregulatory, changes that may follow the inhibition of LH neurons. In the present study, the EEG and autonomic/thermoregulatory effects of a prolonged LH inhibition provoked by the repeated local delivery of the GABAA agonist muscimol were studied in rats kept at thermoneutral (24°C) and at a low (10°C) ambient temperature (Ta), a condition which is known to depress sleep occurrence. Here we show that: 1) at both Tas, LH inhibition promoted a peculiar and sustained bout of NREM sleep characterized by an enhancement of slow-wave activity with no NREM-to-REM sleep transitions; 2) LH inhibition caused a marked transitory decrease in brain temperature at Ta 10°C, but not at Ta 24°C, suggesting that sleep changes induced by LH inhibition at thermoneutrality are not caused by a thermoregulatory impairment. These changes are far different from those observed after the short-term selective inhibition of either orexin or MCH neurons, suggesting that other LH neurons are involved in sleep-wake modulation.

  3. Enhanced Slow-Wave EEG Activity and Thermoregulatory Impairment following the Inhibition of the Lateral Hypothalamus in the Rat

    PubMed Central

    Cerri, Matteo; Vecchio, Flavia Del; Mastrotto, Marco; Luppi, Marco; Martelli, Davide; Perez, Emanuele; Tupone, Domenico; Zamboni, Giovanni; Amici, Roberto

    2014-01-01

    Neurons within the lateral hypothalamus (LH) are thought to be able to evoke behavioural responses that are coordinated with an adequate level of autonomic activity. Recently, the acute pharmacological inhibition of LH has been shown to depress wakefulness and promote NREM sleep, while suppressing REM sleep. These effects have been suggested to be the consequence of the inhibition of specific neuronal populations within the LH, i.e. the orexin and the MCH neurons, respectively. However, the interpretation of these results is limited by the lack of quantitative analysis of the electroencephalographic (EEG) activity that is critical for the assessment of NREM sleep quality and the presence of aborted NREM-to-REM sleep transitions. Furthermore, the lack of evaluation of the autonomic and thermoregulatory effects of the treatment does not exclude the possibility that the wake-sleep changes are merely the consequence of the autonomic, in particular thermoregulatory, changes that may follow the inhibition of LH neurons. In the present study, the EEG and autonomic/thermoregulatory effects of a prolonged LH inhibition provoked by the repeated local delivery of the GABAA agonist muscimol were studied in rats kept at thermoneutral (24°C) and at a low (10°C) ambient temperature (Ta), a condition which is known to depress sleep occurrence. Here we show that: 1) at both Tas, LH inhibition promoted a peculiar and sustained bout of NREM sleep characterized by an enhancement of slow-wave activity with no NREM-to-REM sleep transitions; 2) LH inhibition caused a marked transitory decrease in brain temperature at Ta 10°C, but not at Ta 24°C, suggesting that sleep changes induced by LH inhibition at thermoneutrality are not caused by a thermoregulatory impairment. These changes are far different from those observed after the short-term selective inhibition of either orexin or MCH neurons, suggesting that other LH neurons are involved in sleep-wake modulation. PMID:25398141

  4. Thermoregulatory and cardiovascular responses to creatine, glycerol and alpha lipoic acid in trained cyclists

    PubMed Central

    2012-01-01

    Background It has been shown that supplementation with creatine (Cr) and glycerol (Gly), when combined with glucose (Glu) necessary for the enhancement of Cr uptake by skeletal muscle, induces significant improvements in thermoregulatory and cardiovascular responses during exercise in the heat. Purpose To determine whether Cr/Gly-induced thermoregulatory and cardiovascular responses are maintained when the majority (~75%) of the Glu in the Cr/Gly supplement is replaced with the insulintropic agent alpha lipoic acid (Ala). Methods 22 healthy endurance trained cyclists were randomly assigned to receive either 20 g/day (4 × 5 g/day) of Cr, 2 g .kg-1 BM per day (4 × 0.5 g .kg-1 BM per day) of Gly and 150 g/day (4 × 37.5 g/day) of Glu or 20 g/day (4 × 5 g/day) of Cr monohydrate, 2 g .kg-1 BM per day (4 × 0.5 g .kg-1 BM per day) of Gly (100 g/day (4 × 25 g/day) of Glu and 1000 mg/day (4 × 250 mg/day) of Ala for 7 days for 7 days. Exercise trials were conducted pre- and post-supplementation and involved 40 min of constant-load cycling exercise at 70% O2 max by a self-paced 16.1 km time trial at 30°C and 70% relative humidity. Results Median and range values of TBW increased significantly by 2.1 (1.3-3.3) L and 1.8 (0.2-4.6) L in Cr/Gly/Glu and Cr/Gly/Glu/Ala groups respectively (P = 0.03) and of BM not significantly by 1.8 (0.2-3.0) kg and 1.2 (0.5-2.1) kg in Cr/Gly/Glu and in Cr/Gly/Glu/Ala, respectively (P = 0.75). During constant load exercise, heart rate (HR) and core temperature (Tcore) were significantly lower post-supplementation: HR was reduced on average by 3.3 ± 2.1 beats/min and by 4.8 ± 3.3 beats/min (mean ± SD) and Tcore by 0.2 ± 0.1 (mean ± SD) in the Cr/Gly/Glu and Cr/Gly/Glu/Ala, respectively The reduction in HR and Tcore was not significantly different between the supplementation groups. Conclusions In comparison to the established hyper hydrating Cr

  5. Thermoregulatory and cardiovascular responses to creatine, glycerol and alpha lipoic acid in trained cyclists.

    PubMed

    Polyviou, Thelma P; Pitsiladis, Yannis P; Lee, Wu Chean; Pantazis, Takas; Hambly, Catherine; Speakman, John R; Malkova, Dalia

    2012-06-22

    It has been shown that supplementation with creatine (Cr) and glycerol (Gly), when combined with glucose (Glu) necessary for the enhancement of Cr uptake by skeletal muscle, induces significant improvements in thermoregulatory and cardiovascular responses during exercise in the heat. To determine whether Cr/Gly-induced thermoregulatory and cardiovascular responses are maintained when the majority (~75%) of the Glu in the Cr/Gly supplement is replaced with the insulintropic agent alpha lipoic acid (Ala). 22 healthy endurance trained cyclists were randomly assigned to receive either 20 g/day (4 × 5 g/day) of Cr, 2 g .kg-1 BM per day (4 × 0.5 g .kg-1 BM per day) of Gly and 150 g/day (4 × 37.5 g/day) of Glu or 20 g/day (4 × 5 g/day) of Cr monohydrate, 2 g .kg-1 BM per day (4 × 0.5 g .kg-1 BM per day) of Gly (100 g/day (4 × 25 g/day) of Glu and 1000 mg/day (4 × 250 mg/day) of Ala for 7 days for 7 days. Exercise trials were conducted pre- and post-supplementation and involved 40 min of constant-load cycling exercise at 70% O2 max by a self-paced 16.1 km time trial at 30°C and 70% relative humidity. Median and range values of TBW increased significantly by 2.1 (1.3-3.3) L and 1.8 (0.2-4.6) L in Cr/Gly/Glu and Cr/Gly/Glu/Ala groups respectively (P = 0.03) and of BM not significantly by 1.8 (0.2-3.0) kg and 1.2 (0.5-2.1) kg in Cr/Gly/Glu and in Cr/Gly/Glu/Ala, respectively (P = 0.75). During constant load exercise, heart rate (HR) and core temperature (Tcore) were significantly lower post-supplementation: HR was reduced on average by 3.3 ± 2.1 beats/min and by 4.8 ± 3.3 beats/min (mean ± SD) and Tcore by 0.2 ± 0.1 (mean ± SD) in the Cr/Gly/Glu and Cr/Gly/Glu/Ala, respectively The reduction in HR and Tcore was not significantly different between the supplementation groups. In comparison to the established hyper hydrating Cr/Gly/Glu supplement, supplement containing Cr/Gly/Ala and

  6. A Centroid Model of Species Distribution to Analyize Multi-directional Climate Change Finger Print in Avian Distribution in North America

    NASA Astrophysics Data System (ADS)

    Huang, Q.; Sauer, J.; Dubayah, R.

    2015-12-01

    Species distribution shift (or referred to as "fingerprint of climate change") as a primary mechanism to adapt climate change has been of great interest to ecologists and conservation practitioners. Recent meta-analyses have concluded that a wide range of animal and plant species are already shifting their distribution. However majority of the literature has focused on analyzing recent poleward and elevationally upward shift of species distribution. However if measured only in poleward shifts, the fingerprint of climate change will be underestimated significantly. In this study, we demonstrate a centroid model for range-wide analysis of distribution shifts using the North American Breeding Bird Survey. The centroid model is based on a hierarchical Bayesian framework which models population change within physiographic strata while accounting for several factors affecting species detectability. We used the centroid approach to examine large number of species permanent resident species in North America and evaluated the dreiction and magnitude of their shifting distribution. To examine the inferential ability of mean temperature and precipitation, we test a hypothesis based on climate velocity theory that species would be more likely to shift their distribution or would shift with greater magnitude in in regions with high climate change velocity. For species with significant shifts of distribution, we establish a precipitation model and a temperature model to explain their change of abundance at the strata level. Two models which are composed of mean and extreme climate indices respectively are also established to test the influences of changes in gradual and extreme climate trends.

  7. Biomechanical analysis of the human finger extensor mechanism during isometric pressing.

    PubMed

    Hu, Dan; Howard, David; Ren, Lei

    2014-01-01

    This study investigated the effects of the finger extensor mechanism on the bone-to-bone contact forces at the interphalangeal and metacarpal joints and also on the forces in the intrinsic and extrinsic muscles during finger pressing. This was done with finger postures ranging from very flexed to fully extended. The role of the finger extensor mechanism was investigated by using two alternative finger models, one which omitted the extensor mechanism and another which included it. A six-camera three-dimensional motion analysis system was used to capture the finger posture during maximum voluntary isometric pressing. The fingertip loads were recorded simultaneously using a force plate system. Two three-dimensional biomechanical finger models, a minimal model without extensor mechanism and a full model with extensor mechanism (tendon network), were used to calculate the joint bone-to-bone contact forces and the extrinsic and intrinsic muscle forces. If the full model is assumed to be realistic, then the results suggest some useful biomechanical advantages provided by the tendon network of the extensor mechanism. It was found that the forces in the intrinsic muscles (interosseus group and lumbrical) are significantly reduced by 22% to 61% due to the action of the extensor mechanism, with the greatest reductions in more flexed postures. The bone-to-bone contact force at the MCP joint is reduced by 10% to 41%. This suggests that the extensor mechanism may help to reduce the risk of injury at the finger joints and also to moderate the forces in intrinsic muscles. These apparent biomechanical advantages may be a result of the extensor mechanism's distinctive interconnected fibrous structure, through which the contraction of the intrinsic muscles as flexors of the MCP joint can generate extensions at the DIP and PIP joints.

  8. Biomechanical Analysis of the Human Finger Extensor Mechanism during Isometric Pressing

    PubMed Central

    Hu, Dan; Howard, David; Ren, Lei

    2014-01-01

    This study investigated the effects of the finger extensor mechanism on the bone-to-bone contact forces at the interphalangeal and metacarpal joints and also on the forces in the intrinsic and extrinsic muscles during finger pressing. This was done with finger postures ranging from very flexed to fully extended. The role of the finger extensor mechanism was investigated by using two alternative finger models, one which omitted the extensor mechanism and another which included it. A six-camera three-dimensional motion analysis system was used to capture the finger posture during maximum voluntary isometric pressing. The fingertip loads were recorded simultaneously using a force plate system. Two three-dimensional biomechanical finger models, a minimal model without extensor mechanism and a full model with extensor mechanism (tendon network), were used to calculate the joint bone-to-bone contact forces and the extrinsic and intrinsic muscle forces. If the full model is assumed to be realistic, then the results suggest some useful biomechanical advantages provided by the tendon network of the extensor mechanism. It was found that the forces in the intrinsic muscles (interosseus group and lumbrical) are significantly reduced by 22% to 61% due to the action of the extensor mechanism, with the greatest reductions in more flexed postures. The bone-to-bone contact force at the MCP joint is reduced by 10% to 41%. This suggests that the extensor mechanism may help to reduce the risk of injury at the finger joints and also to moderate the forces in intrinsic muscles. These apparent biomechanical advantages may be a result of the extensor mechanism's distinctive interconnected fibrous structure, through which the contraction of the intrinsic muscles as flexors of the MCP joint can generate extensions at the DIP and PIP joints. PMID:24732789

  9. [Ligament injuries of fingers and thumbs].

    PubMed

    Schmitt, R

    2017-01-01

    Degenerative and traumatic ligament lesions of the carpometacarpal joints frequently occur at the thumb ray, whereas the carpometacarpal amphiarthrosis of other finger rays are rarely affected. The metacarpophalangeal and interphalangeal joints of the thumb and fingers are stabilized by bilaterally running collateral ligaments and palmar plates. At the base of the metacarpophalangeal joints, several ligaments of the extensor hoods guide the extensor tendons and coordinate the fine motoric skills of phalangeal flexing and extending. Several annular and cruciform ligaments hold the flexor tendons close to the finger skeleton. Other than at the wrist, differentiation between dynamic and static instability patterns is possible by physical examination. This review article presents the ligaments of the thumb and the fingers, the traumatic and degenerative lesions as well as the diagnostic capability of x‑rays, cinematography, magnetic resonance imaging (MRI) and MR arthrography.

  10. Spreading and fingering in spin coating

    NASA Astrophysics Data System (ADS)

    Holloway, Kristi E.; Habdas, Piotr; Semsarillar, Naeim; Burfitt, Kim; de Bruyn, John R.

    2007-04-01

    We study the spreading and fingering of drops of silicone oil on a rotating substrate for a range of rotation speeds and drop volumes. The spreading of the drop prior to the onset of fingering is found to follow the theoretically predicted time dependence, but with a large shift in time scale. For the full range of experimental parameters studied, the contact line becomes unstable and fingers develop when the radius of the drop becomes sufficiently large. We study the growth of perturbations around the perimeter of the drop and find the growth rate of the most unstable mode to agree well with the predictions of lubrication theory. The number of fingers which form around the perimeter of the drop is found to be a function of both rotation speed and drop volume, and is also in excellent agreement with theoretical predictions.

  11. Case reports: thumb reconstruction using amputated fingers.

    PubMed

    Hoang, Nguyen T; Staudenmaier, R; Hoehnke, C

    2008-08-01

    Reconstruction of an irreparably amputated thumb in multiple digit amputations using amputated fingers can considerably improve hand function and allows creation of a newly transplanted thumb with acceptable cosmetic and functional attributes. However, the surgery is challenging and rarely reported. We report six cases using this procedure in patients with crushed thumbs unsuitable for replantation. In four of the patients, the remnant of the index finger was replanted on the thumb stump and in another two patients, an amputated middle finger and ring finger were used. The patients had a minimum followup of 12 months (mean, 18 months; range, 12-45 months). All newly transplanted thumbs survived resulting in the patients having satisfactory postoperative hand function and appearance.

  12. Repair of webbed fingers - series (image)

    MedlinePlus

    Syndactyly is the abnormal development of the hand, such that the fingers are fused. The number of ... second surgery, depending on the complexity of the syndactyly. Hospital stays of 1 or 2 days are ...

  13. Finger prosthesis: a boon to handicapped

    PubMed Central

    Gupta, Ridhima; Kumar, Lakshya; Rao, Jitendra; Singh, Kamleshwar

    2013-01-01

    This is a clinical case report of a 52-year-old male patient with four partially missing fingers of the left hand. The article describes the clinical and laboratory procedure of making prosthesis with modern silicone material. A wax pattern was fabricated using the right hand of the patient. A special type of wax was formulated to make the pattern so that it can be easily moulded and carved. Intrinsic and extrinsic staining was also performed to match the adjacent skin colour. The patient was given the finger prosthesis and was asked to use a half glove (sports) to mask the junction between the prosthesis and the normal tissue. It also provides additional retention to the artificial fingers. The patient felt his social acceptance improved after wearing the finger prosthesis. PMID:23988821

  14. Salt-finger convection under reduced gravity

    NASA Technical Reports Server (NTRS)

    Chen, C. F.

    1990-01-01

    Salt-finger convection in a double-diffusive system is a motion driven by the release of gravitational potential due to differential diffusion rates. Because of the fact that the destabilizing effect of the concentration gradient is amplified by the Lewis number (the ratio of thermal diffusivity to solute diffusivity) salt-finger convection can be generated at very much reduced gravity levels. This effect may be of importance in the directional solidification of binary alloys carried out in space. The transport of solute and heat by salt-finger convection at microgravity conditions is considered; instability arising from surface tension gradients, the Marangoni instability, is discussed, and the possible consequences of combined salt-finger and Marangoni instability are considered.

  15. Clinical implications of Mycobacterium chimaera detection in thermoregulatory devices used for extracorporeal membrane oxygenation (ECMO), Germany, 2015 to 2016.

    PubMed

    Trudzinski, Franziska C; Schlotthauer, Uwe; Kamp, Annegret; Hennemann, Kai; Muellenbach, Ralf M; Reischl, Udo; Gärtner, Barbara; Wilkens, Heinrike; Bals, Robert; Herrmann, Mathias; Lepper, Philipp M; Becker, Sören L

    2016-11-17

    Mycobacterium chimaera, a non-tuberculous mycobacterium, was recently identified as causative agent of deep-seated infections in patients who had previously undergone open-chest cardiac surgery. Outbreak investigations suggested an aerosol-borne pathogen transmission originating from water contained in heater-cooler units (HCUs) used during cardiac surgery. Similar thermoregulatory devices are used for extracorporeal membrane oxygenation (ECMO) and M. chimaera might also be detectable in ECMO treatment settings. We performed a prospective microbiological study investigating the occurrence of M. chimaera in water from ECMO systems and in environmental samples, and a retrospective clinical review of possible ECMO-related mycobacterial infections among patients in a pneumological intensive care unit. We detected M. chimaera in 9 of 18 water samples from 10 different thermoregulatory ECMO devices; no mycobacteria were found in the nine room air samples and other environmental samples. Among 118 ECMO patients, 76 had bronchial specimens analysed for mycobacteria and M. chimaera was found in three individuals without signs of mycobacterial infection at the time of sampling. We conclude that M. chimaera can be detected in water samples from ECMO-associated thermoregulatory devices and might potentially pose patients at risk of infection. Further research is warranted to elucidate the clinical significance of M. chimaera in ECMO treatment settings. This article is copyright of The Authors, 2016.

  16. Clinical implications of Mycobacterium chimaera detection in thermoregulatory devices used for extracorporeal membrane oxygenation (ECMO), Germany, 2015 to 2016

    PubMed Central

    Trudzinski, Franziska C.; Schlotthauer, Uwe; Kamp, Annegret; Hennemann, Kai; Muellenbach, Ralf M.; Reischl, Udo; Gärtner, Barbara; Wilkens, Heinrike; Bals, Robert; Herrmann, Mathias; Lepper, Philipp M.; Becker, Sören L.

    2016-01-01

    Mycobacterium chimaera, a non-tuberculous mycobacterium, was recently identified as causative agent of deep-seated infections in patients who had previously undergone open-chest cardiac surgery. Outbreak investigations suggested an aerosol-borne pathogen transmission originating from water contained in heater-cooler units (HCUs) used during cardiac surgery. Similar thermoregulatory devices are used for extracorporeal membrane oxygenation (ECMO) and M. chimaera might also be detectable in ECMO treatment settings. We performed a prospective microbiological study investigating the occurrence of M. chimaera in water from ECMO systems and in environmental samples, and a retrospective clinical review of possible ECMO-related mycobacterial infections among patients in a pneumological intensive care unit. We detected M. chimaera in 9 of 18 water samples from 10 different thermoregulatory ECMO devices; no mycobacteria were found in the nine room air samples and other environmental samples. Among 118 ECMO patients, 76 had bronchial specimens analysed for mycobacteria and M. chimaera was found in three individuals without signs of mycobacterial infection at the time of sampling. We conclude that M. chimaera can be detected in water samples from ECMO-associated thermoregulatory devices and might potentially pose patients at risk of infection. Further research is warranted to elucidate the clinical significance of M. chimaera in ECMO treatment settings. PMID:27918254

  17. Daily rhythmicity of the thermoregulatory responses of locally adapted Brazilian sheep in a semiarid environment

    NASA Astrophysics Data System (ADS)

    da Silva, Wilma Emanuela; Leite, Jacinara Hody Gurgel Morais; de Sousa, José Ernandes Rufino; Costa, Wirton Peixoto; da Silva, Wallace Sostene Tavares; Guilhermino, Magda Maria; Asensio, Luis Alberto Bermejo; Façanha, Débora Andréa Evangelista

    2017-01-01

    The goal of this study was to evaluate the daily rhythmicity of the thermoregulatory responses of Morada Nova ewes that were raised in a semiarid environment. The experiment was conducted during the dry season. Data were collected from 5:00 a.m. to 4:00 a.m.. Samples were taken over the course of 8 days, with a 1-week interval between sampling periods. During each day that the data were collected, animals were measured once an hour for 24 h in an area directly exposed to solar radiation. The environment was characterized by measuring the following variables: air temperature (TA), relative humidity (RH), Black Globe Humidity Index (BGHI), radiant heat load (RHL), and wind speed (WS). Physiological variables that were measured included rectal temperature (RT, °C), respiratory rate (RR, breaths/min), surface temperature (ST, °C), and sweating rate (SR, g m2 h-1). We observed that RT, RR, and ST increased as environmental conditions became more stressful. Specifically, environmental conditions became more stressful as RHL, air temperature, and BGHI increased, while RH decreased. All physiological variables of the animals were strongly affected by the time of the day: environmental variables changed drastically between nighttime and noon. Physiological parameters increased sharply from the morning (7:00 a.m.-10:00 a.m.) until noon (11:00 a.m.-2:00 p.m.), except for sweating rate. After noon, these variables began to drop until nighttime (11:00 p.m.-6:00 am), and values of the main physiological indexes were stable during this period. The Morada Nova breed exhibited daily cyclic variations in thermoregulatory responses. Evaporative heat loss mechanisms were triggered during the most stressful times of the day. The first mechanism that animals used was panting, which was an immediate response to environmental heat stress. Cutaneous evaporation had a slower response mechanism to environmental heat stress. Homeothermy conditions were restored to the animals at

  18. Shifts in thermoregulatory strategy during ontogeny in harp seals (Pagophilus groenlandicus).

    PubMed

    Pearson, Linnea E; Liwanag, Heather E M; Hammill, Mike O; Burns, Jennifer M

    2014-08-01

    Heat balance can be difficult for young and/or small animals in polar regions because environmental conditions in combination with small body size or physiological immaturity can increase heat loss. We investigated how thermoregulatory patterns change with ontogeny in 5 age classes of harp seal (Pagophilus groenlandicus) from birth to post-molt to further understand the timing of thermoregulatory development in relation to their potential vulnerability to ongoing fluctuations in the extent and stability of Arctic pack ice. We measured changes in the amount, conductivity, and resistance of the seal pups׳ insulative layers (blubber and fur), the potential for endogenous heat-generation by shivering (muscle enzyme activity), and nonshivering thermogenesis (NST; brown adipose tissue (BAT) uncoupling protein 1 (UCP1) expression and mitochondrial density). There was no significant difference in blubber conductivity among age classes, though the amount of blubber insulation significantly increased from birth to weaning. Pelage conductivity was low (0.12±0.01Wm(-1)°C(-1)) except in 9-day old pups (0.40±0.08Wm(-1)°C(-1)); the significantly higher conductivity may signal the beginning of the molt, and this age group may be the most vulnerable to early water entry. Citrate synthase activity significantly increased (49.68±3.26 to 75.08±3.52μmolmin(-1)gwetweight(-1)) in the muscle; however it is unlikely that increasing a single enzyme greatly impacts heat generation. BAT of younger pups contained UCP1, though expression and mitochondrial density quickly declined, and the ability of pups to produce heat via NST was lost by weaning. While total thermal resistance did not differ, neonatal and early nursing animals gained the majority of their thermal resistance from lanugo (82.5±0.03%); however, lanugo is not insulative when wet, and NST may be important to maintain euthermia and dry the coat if early immersion in water occurs. By late nursing, blubber seems sufficient

  19. Thermoregulatory Responses and Hydration Practices in Heat-Acclimatized Adolescents During Preseason High School Football

    PubMed Central

    Yeargin, Susan Walker; Casa, Douglas J.; Judelson, Daniel A.; McDermott, Brendon P.; Ganio, Matthew S.; Lee, Elaine C.; Lopez, Rebecca M.; Stearns, Rebecca L.; Anderson, Jeffrey M.; Armstrong, Lawrence E.; Kraemer, William J.; Maresh, Carl M.

    2010-01-01

    Abstract Context: Previous researchers have not investigated the thermoregulatory responses to multiple consecutive days of American football in adolescents. Objective: To examine the thermoregulatory and hydration responses of high school players during formal preseason football practices. Design: Observational study. Setting: Players practiced outdoors in late August once per day on days 1 through 5, twice per day on days 6 and 7, and once per day on days 8 through 10. Maximum wet bulb globe temperature averaged 23 ± 4°C. Patients or Other Participants: Twenty-five heat-acclimatized adolescent boys (age  =  15 ± 1 years, height  =  180 ± 8 cm, mass  =  81.4 ± 15.8 kg, body fat  =  12 ± 5%, Tanner stage  =  4 ± 1). Main Outcome Measure(s): We observed participants within and across preseason practices of football. Measures included gastrointestinal temperature (TGI), urine osmolality, sweat rate, forearm sweat composition, fluid consumption, testosterone to cortisol ratio, perceptual measures of thirst, perceptual measures of thermal sensation, a modified Environmental Symptoms Questionnaire, and knowledge questionnaires assessing the participants' understanding of heat illnesses and hydration. Results were analyzed for differences across time and were compared between younger (14–15 years, n  =  13) and older (16–17 years, n  =  12) participants. Results: Maximum daily TGI values remained less than 40°C and were correlated with maximum wet bulb globe temperature (r  =  0.59, P  =  .009). Average urine osmolality indicated that participants generally experienced minimal to moderate hypohydration before (881 ± 285 mOsmol/kg) and after (856 ± 259 mOsmol/kg) each practice as a result of replacing approximately two-thirds of their sweat losses during exercise but inadequately rehydrating between practices. Age did not affect most variables; however, sweat rate was lower in younger participants (0.6 ± 0.2

  20. Daily rhythmicity of the thermoregulatory responses of locally adapted Brazilian sheep in a semiarid environment

    NASA Astrophysics Data System (ADS)

    da Silva, Wilma Emanuela; Leite, Jacinara Hody Gurgel Morais; de Sousa, José Ernandes Rufino; Costa, Wirton Peixoto; da Silva, Wallace Sostene Tavares; Guilhermino, Magda Maria; Asensio, Luis Alberto Bermejo; Façanha, Débora Andréa Evangelista

    2017-07-01

    The goal of this study was to evaluate the daily rhythmicity of the thermoregulatory responses of Morada Nova ewes that were raised in a semiarid environment. The experiment was conducted during the dry season. Data were collected from 5:00 a.m. to 4:00 a.m.. Samples were taken over the course of 8 days, with a 1-week interval between sampling periods. During each day that the data were collected, animals were measured once an hour for 24 h in an area directly exposed to solar radiation. The environment was characterized by measuring the following variables: air temperature (TA), relative humidity (RH), Black Globe Humidity Index (BGHI), radiant heat load (RHL), and wind speed (WS). Physiological variables that were measured included rectal temperature (RT, °C), respiratory rate (RR, breaths/min), surface temperature (ST, °C), and sweating rate (SR, g m2 h-1). We observed that RT, RR, and ST increased as environmental conditions became more stressful. Specifically, environmental conditions became more stressful as RHL, air temperature, and BGHI increased, while RH decreased. All physiological variables of the animals were strongly affected by the time of the day: environmental variables changed drastically between nighttime and noon. Physiological parameters increased sharply from the morning (7:00 a.m.-10:00 a.m.) until noon (11:00 a.m.-2:00 p.m.), except for sweating rate. After noon, these variables began to drop until nighttime (11:00 p.m.-6:00 am), and values of the main physiological indexes were stable during this period. The Morada Nova breed exhibited daily cyclic variations in thermoregulatory responses. Evaporative heat loss mechanisms were triggered during the most stressful times of the day. The first mechanism that animals used was panting, which was an immediate response to environmental heat stress. Cutaneous evaporation had a slower response mechanism to environmental heat stress. Homeothermy conditions were restored to the animals at

  1. Finger Lake Region, NY State, USA

    NASA Technical Reports Server (NTRS)

    1992-01-01

    This view of the central portion of upstate New York, centers on the Finger Lakes. The large city on the shore of Lake Ontario, is Rochester. Although the city, being a business, educational and technical center, has no heavy industry, the outline of the city shows fairly well in the snow, but not as well as the outlines of industrial cities elsewhere in the world. The Finger Lakes are large linear lakes carved out by glaciers during the last ice age.

  2. Finger Lake Region, NY State, USA

    NASA Image and Video Library

    1992-04-02

    This view of the central portion of upstate New York, centers on the Finger Lakes. The large city on the shore of Lake Ontario, is Rochester. Although the city, being a business, educational and technical center, has no heavy industry, the outline of the city shows fairly well in the snow, but not as well as the outlines of industrial cities elsewhere in the world. The Finger Lakes are large linear lakes carved out by glaciers during the last ice age.

  3. Reverse Pressure Capable Finger Seal (Preprint)

    DTIC Science & Technology

    2012-01-01

    Currently, the typical solution for locations requiring reverse capable sealing are labyrinth seals which can exhibit significantly higher leakage...AFRL-RX-WP-TP-2012-0215 REVERSE PRESSURE CAPABLE FINGER SEAL (PREPRINT) Nathan Gibson and Joe Yanof Honeywell International, Inc...AND SUBTITLE REVERSE PRESSURE CAPABLE FINGER SEAL (PREPRINT) 5a. CONTRACT NUMBER FA8650-09-D-2925-0003 5b. GRANT NUMBER 5c. PROGRAM ELEMENT

  4. Contributions and co-ordination of individual fingers in multiple finger prehension.

    PubMed

    Kinoshita, H; Kawai, S; Ikuta, K

    1995-06-01

    The contributions and co-ordination of external finger grip forces were examined during a lifting task with a precision grip using multiple fingers. The subjects (n = 10) lifted a force transducer-equipped grip apparatus. Grip force from each of the five fingers was continuously measured under different object weight (200 g, 400 g and 800 g) and surface structure (plastic and sandpaper) conditions. The effect of five-, four-, and three-finger grip modes was also examined. It was found that variation of object weight or surface friction resulted in change of the total grip force magnitude; the largest change in finger force, was that for the index finger, followed by the middle, ring, and little fingers. Percentage contribution of static grip force to the total grip force for the index, middle, ring, and little fingers was 42.0%, 27.4%, 17.6% and 12.9%, respectively. These values were fairly constant for all object weight conditions, as well as for all surface friction conditions, suggesting that all individual finger force adjustments for light loads less than 800 g are controlled comprehensively simply by using a single common scaling value. A higher surface friction provided faster lifting initiation and required lesser grip force exertion, indicating advantageous effect of a non-slippery surface over a slippery surface. The results indicate that nearly 40% force reduction can be obtained when a non-slippery surface is used. Variation in grip mode changed the total grip force, i.e., the fewer the number of fingers, the greater the total grip force. The percent value of static grip force for the index, middle, and ring fingers in the four-finger grip mode was 42.7%, 32.5%, and 24.7%, respectively, and that for the index and middle fingers in the three-finger grip mode was 43.0% and 56.9%, respectively. Therefore, the grip mode was found to influence the force contributions of the middle and ring fingers, but not of the index finger.

  5. Improved DNA binding specificity from polyzinc finger peptides by using strings of two-finger units

    PubMed Central

    Moore, Michael; Klug, Aaron; Choo, Yen

    2001-01-01

    Multizinc finger peptides are likely to reach increased prominence in the search for the “ideal” designer transcription factor for in vivo applications such as gene therapy. However, for these treatments to be effective and safe, the peptides must bind with high affinity and, more importantly, with great specificity. Our previous research has shown that zinc finger arrays can be made to bind 18 bp of DNA with picomolar affinity, but also has suggested that arrays of fingers also may bind tightly to related sequences. This work addresses the question of zinc finger DNA binding specificity. We show that by changing the way in which zinc finger arrays are constructed—by linking three two-finger domains rather than two three-finger units—far greater target specificity can be achieved through increased discrimination against mutated or closely related sequences. These new peptides have the added capability of being able to span two short gaps of unbound DNA, although still binding with picomolar affinity to their target sites. We believe that this new method of constructing zinc finger arrays will offer greater efficacy in the fields of gene therapy and in the production of transgenic organisms than previously reported zinc finger arrays. PMID:11171969

  6. On the continuum-scale simulation of gravity-driven fingers with hysteretic Richards equation: Trucation error induced numerical artifacts

    SciTech Connect

    ELIASSI,MEHDI; GLASS JR.,ROBERT J.

    2000-03-08

    The authors consider the ability of the numerical solution of Richards equation to model gravity-driven fingers. Although gravity-driven fingers can be easily simulated using a partial downwind averaging method, they find the fingers are purely artificial, generated by the combined effects of truncation error induced oscillations and capillary hysteresis. Since Richards equation can only yield a monotonic solution for standard constitutive relations and constant flux boundary conditions, it is not the valid governing equation to model gravity-driven fingers, and therefore is also suspect for unsaturated flow in initially dry, highly nonlinear, and hysteretic media where these fingers occur. However, analysis of truncation error at the wetting front for the partial downwind method suggests the required mathematical behavior of a more comprehensive and physically based modeling approach for this region of parameter space.

  7. New Finger Biometric Method Using Near Infrared Imaging

    PubMed Central

    Lee, Eui Chul; Jung, Hyunwoo; Kim, Daeyeoul

    2011-01-01

    In this paper, we propose a new finger biometric method. Infrared finger images are first captured, and then feature extraction is performed using a modified Gaussian high-pass filter through binarization, local binary pattern (LBP), and local derivative pattern (LDP) methods. Infrared finger images include the multimodal features of finger veins and finger geometries. Instead of extracting each feature using different methods, the modified Gaussian high-pass filter is fully convolved. Therefore, the extracted binary patterns of finger images include the multimodal features of veins and finger geometries. Experimental results show that the proposed method has an error rate of 0.13%. PMID:22163741

  8. Finger multibiometric cryptosystems: fusion strategy and template security

    NASA Astrophysics Data System (ADS)

    Peng, Jialiang; Li, Qiong; Abd El-Latif, Ahmed A.; Niu, Xiamu

    2014-03-01

    We address two critical issues in the design of a finger multibiometric system, i.e., fusion strategy and template security. First, three fusion strategies (feature-level, score-level, and decision-level fusions) with the corresponding template protection technique are proposed as the finger multibiometric cryptosystems to protect multiple finger biometric templates of fingerprint, finger vein, finger knuckle print, and finger shape modalities. Second, we theoretically analyze different fusion strategies for finger multibiometric cryptosystems with respect to their impact on security and recognition accuracy. Finally, the performance of finger multibiometric cryptosystems at different fusion levels is investigated on a merged finger multimodal biometric database. The comparative results suggest that the proposed finger multibiometric cryptosystem at feature-level fusion outperforms other approaches in terms of verification performance and template security.

  9. Finger tips detection for two handed gesture recognition

    NASA Astrophysics Data System (ADS)

    Bhuyan, M. K.; Kar, Mithun Kumar; Neog, Debanga Raj

    2011-10-01

    In this paper, a novel algorithm is proposed for fingertips detection in view of two-handed static hand pose recognition. In our method, finger tips of both hands are detected after detecting hand regions by skin color-based segmentation. At first, the face is removed in the image by using Haar classifier and subsequently, the regions corresponding to the gesturing hands are isolated by a region labeling technique. Next, the key geometric features characterizing gesturing hands are extracted for two hands. Finally, for all possible/allowable finger movements, a probabilistic model is developed for pose recognition. Proposed method can be employed in a variety of applications like sign language recognition and human-robot-interactions etc.

  10. Rehabilitation of single finger amputation with customized silicone prosthesis

    PubMed Central

    Yadav, Niharika; Chand, Pooran; Jurel, Sunit Kumar

    2016-01-01

    Finger amputations are common in accidents at home, work, and play. Apart from trauma, congenital disease and deformity also leads to finger amputation. This results in loss of function, loss of sensation as well as loss of body image. Finger prosthesis offers psychological support and social acceptance in such cases. This clinical report describes a method to fabricate ring retained silicone finger prosthesis in a patient with partial finger loss. PMID:28163487

  11. The Significance of Fingers and Lobes in Emplacement of Sill Complexes: Insights From Field Data

    NASA Astrophysics Data System (ADS)

    Schofield, N.; Thomson, K.; Stevenson, C.; Hutton, D.

    2007-12-01

    The understanding of the emplacement of sill complexes has developed greatly of the last decade from insights gained from 3D seismic data. Particularly, the identification of structures, such as units and lobes in the order of 100s m - km scale, which make up individual sills (e.g. Thomson & Hutton, 2004, Bull Volcanol, 66, 364-375). However the formation and significance of these structures in terms of the emplacement of sill complexes is only partially understood. We present field data from planar-segmented sills on the Isle of Skye, Scotland and saucer- shaped sills in the Karoo Basin, S Africa. In both of these areas constituent lobes can be confirmed but we have also observed smaller scale finger-like structures in the order of 10s - 100s m, which appear to make up these lobes. In planar-segmented sills (Skye) fingers are aligned along the axis of the lobes and have a NNW trend, consistent with a structurally controlled emplacement direction. In saucer-shaped sills (Karoo) with no obvious structural control, fingers are oriented radially about lobes, radiating outwards from the centre of the saucer. Fingers initially propagate separately, thickening vertically and laterally and coalescing to form lobes. Once the fingers have coalesced, the sill continues to thicken vertically. Finger structures clearly have a fundamental role in the initial propagation of sills. Detailed examination of fingers of the Golden Valley Sill in the Karoo Basin shows that there is a regular and predictable spacing between the crests and troughs between individual fingers. This spacing is consistent within individual lobes but varies from lobe to lobe. This implies that sills are constructed in a stepwise fashion and that models which assume one discrete intrusion event may be an oversimplification. The regular spacing of fingers also leads us to suspect that their wavelength may provide information about the propagation of the sill. It is proposed that the wavelength of the fingers

  12. Economic thermoregulatory response explains mismatch between thermal physiology and behaviour in newts.

    PubMed

    Gvoždík, Lumír; Kristín, Peter

    2017-03-15

    Temperature is an important factor determining distribution and abundance of organisms. Predicting the impact of warming climate on ectotherm populations requires information about species' thermal requirements, i.e. their so-called 'thermal niche'. The characterization of thermal niche remains a complicated task. We compared the applicability of two indirect approaches, based on reaction norm (aerobic scope curve) and optimality (preferred body temperature) concepts, for indirect estimation of thermal niche while using newts, Ichthyosaura alpestris, as a study system. If the two approaches are linked, then digesting newts should keep their body temperatures close to values maximizing aerobic scope for digestion. After feeding, newts maintained their body temperatures within a narrower range than did hungry individuals. The range of preferred body temperatures was well below the temperature maximizing aerobic scope for digestion. Optimal temperatures for factorial aerobic scope fell within the preferred body temperature range of digesting individuals. We conclude that digesting newts prefer body temperatures that are optimal for the maximum aerobic performance but relative to the maintenance costs. What might be termed the 'economic' thermoregulatory response explains the mismatch between thermal physiology and behaviour in this system.

  13. The particularities of a remote islet shape the thermoregulatory profile of an endemic Mediterranean lizard.

    PubMed

    Pafilis, Panayiotis; Lymberakis, Petros; Sagonas, Kostas; Valakos, Efstratios

    2016-10-01

    Environmental temperatures considerably affect the reptilian ability for thermoregulation and harsh climatic conditions may impose a highly effective body temperature regulation to lizards. Such demanding conditions are more common to extreme mainland habitats (e.g. deserts or mountains). To the contrary, islands have more benign climate conditions thanks to the thermal buffering effect of the surrounding sea. However, this favorable effect may be eliminated in small size islets where the scarcity of thermal shelters and exposure to high winds create challenging conditions. Here we investigate the impact of a tough islet habitat on the thermoregulation of Podarcis levendis, a lacertid lizard endemic to two rocky islets in the north Cretan Sea, Greece. To evaluate the thermoregulatory effectiveness of P. levendis we measured operative and body temperatures in the field and the preferred body temperatures in the lab. Analyses of the thermal data revealed an accurate, precise, and effective thermoregulator, achieving very high thermoregulation values (E =0.91, de¯-db¯ =7.6). This high effectiveness comes to compensate living in an inhospitable habitat as the operative temperatures denote (de =7.79). Our findings, together with the limited published literature, suggested the lack of a general pattern for all insular lizards and indicated a possible deviation for islet habitats. Copyright © 2016 Elsevier Ltd. All rights reserved.

  14. An intraoral thermoregulatory organ in the bowhead whale (Balaena mysticetus), the corpus cavernosum maxillaris.

    PubMed

    Ford, Thomas J; Werth, Alexander J; George, J Craig

    2013-04-01

    The novel observation of a palatal retial organ in the bowhead whale (Balaena mysticetus) is reported, with characterization of its form and function. This bulbous ridge of highly vascularized tissue, here designated the corpus cavernosum maxillaris, runs along the center of the hard palate, expanding cranially to form two large lobes that terminate under the tip of the rostral palate, with another enlarged node at the caudal terminus. Gross anatomical and microscopic observation of tissue sections discloses a web-like internal mass with a large blood volume. Histological examination reveals large numbers of blood vessels and vascular as well as extravascular spaces resembling a blood-filled, erectile sponge. These spaces, as well as accompanying blood vessels, extend to the base of the epithelium. We contend that this organ provides a thermoregulatory adaptation by which bowhead whales (1) control heat loss by transferring internal, metabolically generated body heat to cold seawater and (2) protect the brain from hyperthermia. We postulate that this organ may play additional roles in baleen growth and in detecting prey, and that its ability to dissipate heat might maintain proper operating temperature for palatal mechanoreceptors or chemoreceptors to detect the presence and density of intraoral prey.

  15. Thermoregulatory behaviour affects prevalence of chytrid fungal infection in a wild population of Panamanian golden frogs

    PubMed Central

    Richards-Zawacki, Corinne L.

    2010-01-01

    Predicting how climate change will affect disease dynamics requires an understanding of how the environment affects host–pathogen interactions. For amphibians, global declines and extinctions have been linked to a pathogenic chytrid fungus, Batrachochytrium dendrobatidis. Using a combination of body temperature measurements and disease assays conducted before and after the arrival of B. dendrobatidis, this study tested the hypothesis that body temperature affects the prevalence of infection in a wild population of Panamanian golden frogs (Atelopus zeteki). The timing of first detection of the fungus was consistent with that of a wave of epidemic infections spreading south and eastward through Central America. During the epidemic, many golden frogs modified their thermoregulatory behaviour, raising body temperatures above their normal set point. Odds of infection decreased with increasing body temperature, demonstrating that even slight environmental or behavioural changes have the potential to affect an individual's vulnerability to infection. The thermal dependency of the relationship between B. dendrobatidis and its amphibian hosts demonstrates how the progression of an epidemic can be influenced by complex interactions between host and pathogen phenotypes and the environments in which they are found. PMID:19864287

  16. Thermoregulatory behaviour affects prevalence of chytrid fungal infection in a wild population of Panamanian golden frogs.

    PubMed

    Richards-Zawacki, Corinne L

    2010-02-22

    Predicting how climate change will affect disease dynamics requires an understanding of how the environment affects host-pathogen interactions. For amphibians, global declines and extinctions have been linked to a pathogenic chytrid fungus, Batrachochytrium dendrobatidis. Using a combination of body temperature measurements and disease assays conducted before and after the arrival of B. dendrobatidis, this study tested the hypothesis that body temperature affects the prevalence of infection in a wild population of Panamanian golden frogs (Atelopus zeteki). The timing of first detection of the fungus was consistent with that of a wave of epidemic infections spreading south and eastward through Central America. During the epidemic, many golden frogs modified their thermoregulatory behaviour, raising body temperatures above their normal set point. Odds of infection decreased with increasing body temperature, demonstrating that even slight environmental or behavioural changes have the potential to affect an individual's vulnerability to infection. The thermal dependency of the relationship between B. dendrobatidis and its amphibian hosts demonstrates how the progression of an epidemic can be influenced by complex interactions between host and pathogen phenotypes and the environments in which they are found.

  17. Thermoregulatory and subjective responses of clothed men in the cold during continuous and intermittent exercise.

    PubMed

    Gavhed, D C; Nielsen, R; Holmér, I

    1991-01-01

    Thermoregulatory and thermal subjective responses were studied in ten male, clothed subjects during continuous (C) and intermittent (I) exercise at the same average level of oxygen consumption. The subjects performed both I and C twice, dressed in two different three-layer cold-protective clothing ensembles of two thermal insulation levels [total clothing insulation = 2.59 clo (L) and 3.20 clo (H)]. Experiments were carried out at an ambient temperature of -10 degrees C. Rectal temperatures increased similarly in both types of exercise. Mean skin temperature (Tsk) was lower in I compared to C with both levels of clothing insulation. Over the last 0.5 h of the experiment Tsk was approximately 1.3 degrees C lower in I than in C for clothing L. The skin evaporation rate was higher in clothing H than L but did not differ between I and C. Subjective ratings for thermal sensations of the whole body (BTS) and hands were close to neutral in I and around slightly warm in C. The BTS was lower in I than in C and was lower in L compared to H. It was concluded that, at equal average energy expenditure, thermal responses to intermittent and continuous exercise in the cold differ in clothed subjects, principally as a result of different patterns of heat exchange.

  18. Atropine, diazepam, and physostigmine: Thermoregulatory effects in the heat-stressed rat

    SciTech Connect

    Matthew, C.B.; Hubbard, R.W.; Francesconi, R.P. )

    1989-01-01

    The authors have previously reported that administration of atropine (A) to unrestrained, sedentary, heat-stressed rats resulted in a dose dependent increase in heating rate. Additionally, we have demonstrated that the decrements in treadmill endurance and increments in heating rate of physostigmine (PH)-treated running rats can both be restored to control levels by pretreating the animals with A and diazepam (D). Our objective in the present work was to determine if the administration of D+PH to A-treated unrestrained, sedentary, heat-stressed rats could improve their thermal tolerance. The following drugs were administered singly via lateral tail vein: vehicle-control (C), A (200 ug/kg), D (500 ug/kg), and PH (200 ug/kg). After drug administration, the rats were heat-stressed until a core temperature of 42.6{degree}C was attained when they were removed to a 26{degree}C chamber. The heating rates ({degree}C/min) and tolerance times (min) of the respective groups were: C- 0.02, 235; A- 0.08, 58; A+D- 0.06, 94; and A+D+PH- 0.04, 143. Administration of D with A significantly decreased heating rate, and D+PH more than doubled the thermal tolerance of A-treated rats. Thus, the combination of A+D+PH not only restores PH- induced performance and thermoregulatory decrements of rats exercised in a moderate environment, but also reduces A- induced heat intolerance.

  19. Changes in ambient temperature at the onset of thermoregulatory responses in exercise-trained rats

    NASA Astrophysics Data System (ADS)

    Sugimoto, N.; Sakurada, S.; Shido, O.

    Spontaneous running in a wheel has emerged as a useful method of exercise in rodents. We investigated how exercise training with a running wheel affects ambient temperatures (Ta) at the onset of thermoregulatory responses in rats. Female rats were allowed to run freely in the wheel for 6 months. Sedentary control rats did not exercise during the same period. After the exercise training period, they were loosely restrained and Ta values at the onset of tail skin vasodilation and cold- induced thermogenesis were determined by raising or lowering Ta. Resting levels of core temperature and heat production of the exercise-trained rats were significantly higher than those of the controls. Ta values at the onset of tail skin vasodilation and cold-induced thermogenesis of the exercise-trained rats were higher than those of the controls. The results suggest that, in rats, exercise training with a running wheel elevates ambient temperatures for heat loss and heat production, which may then contribute to maintaining the core temperature at a high level.

  20. Effects of sleep on the cardiovascular and thermoregulatory systems: a possible role for hypocretins.

    PubMed

    Schwimmer, H; Stauss, H M; Abboud, F; Nishino, S; Mignot, E; Zeitzer, J M

    2010-10-01

    Sleep influences the cardiovascular, endocrine, and thermoregulatory systems. Each of these systems may be affected by the activity of hypocretin (orexin)-producing neurons, which are involved in the etiology of narcolepsy. We examined sleep in male rats, either hypocretin neuron-ablated orexin/ataxin-3 transgenic (narcoleptic) rats or their wild-type littermates. We simultaneously monitored electroencephalographic and electromyographic activity, core body temperature, tail temperature, blood pressure, electrocardiographic activity, and locomotion. We analyzed the daily patterns of these variables, parsing sleep and circadian components and changes between states of sleep. We also analyzed the baroreceptor reflex. Our results show that while core temperature and heart rate are affected by both sleep and time of day, blood pressure is mostly affected by sleep. As expected, we found that both blood pressure and heart rate were acutely affected by sleep state transitions in both genotypes. Interestingly, hypocretin neuron-ablated rats have significantly lower systolic and diastolic blood pressure during all sleep stages (non-rapid eye movement, rapid eye movement) and while awake (quiet, active). Thus, while hypocretins are critical for the normal temporal structure of sleep and wakefulness, they also appear to be important in regulating baseline blood pressure and possibly in modulating the effects of sleep on blood pressure.

  1. The mouse thermoregulatory system: Its impact on translating biomedical data to humans.

    PubMed

    Gordon, Christopher J

    2017-10-01

    The laboratory mouse has become the predominant test species in biomedical research. The number of papers that translate or extrapolate data from mouse to human has grown exponentially since the year 2000. There are many physiological and anatomical factors to consider in the process of extrapolating data from one species to another. Body temperature is, of course, a critical determinant in extrapolation because it has a direct impact on metabolism, cardiovascular function, drug efficacy, pharmacokinetics of toxins and drugs, and many other effects. While most would consider the thermoregulatory system of mice to be sufficiently stable and predictable as to not be a cause for concern, the thermal physiology of mice does in fact present unique challenges to the biomedical researcher. A variable and unstable core temperature, high metabolic rate, preference for warm temperatures, large surface area: body mass ratio, and high rate of thermal conductance, are some of the key factors of mice that can affect the interpretation and translation of data to humans. It is the intent of this brief review to enlighten researchers studying interspecies translation of biomedical data on the salient facets of the mouse thermal physiology and show how extrapolation in fields such as physiology, psychology, nutrition, pharmacology, toxicology, and pathology. Published by Elsevier Inc.

  2. Plasticity of thermoregulatory behavior in leopard geckos (Eublepharis macularius, Blyth 1954).

    PubMed

    Craioveanu, Octavian; Craioveanu, Cristina; Mireşan, Vioara

    2017-07-01

    Studies on thermoregulation in nocturnal lizards have shown that their thermal regimes are similar to those of diurnal lizards, even though they hide during the daytime and are active mostly at night, when heat sources are very scarce. As a result, nocturnal lizards display an active thermoregulatory behavior consisting of seeking warm shelters to hide during the daytime, using accumulated heat for the nocturnal activity. Based on this information, we hypothesize that when leopard geckos (Eublepharis macularius, Blyth 1954) are presented with the choice of safety in cool shelters or vulnerability in heated open areas, suitable temperature will prevail in importance, i.e. they will trade the advantages provided by the shelter for an exposed, but physiologically necessary heat source. Data on the time juvenile E. macularius spent in shelters, and in open areas along a thermal gradient and under a 12/12 hr photoperiod, from eight individuals confirmed our hypothesis. We found that, not only did they select heat sources over shelters, but, along with the light/dark cycle, temperature may also represent a cue for activity. Additionally we found that substrate moisture plays an important role in shelter preference. © 2017 Wiley Periodicals, Inc.

  3. Reprint of: The effectiveness of common thermo-regulatory behaviours in a cool temperate grasshopper.

    PubMed

    Harris, Rebecca M B; McQuillan, Peter; Hughes, Lesley

    2015-12-01

    Behavioural thermoregulation has the potential to alleviate the short-term impacts of climate change on some small ectotherms, without the need for changes to species distributions or genetic adaptation. We illustrate this by measuring the effect of behaviour in a cool temperate species of grasshopper (Phaulacridium vittatum) over a range of spatial and temporal scales in laboratory and natural field experiments. Microhabitat selection at the site scale was tested in free-ranging grasshoppers and related to changing thermal quality over a daily period. Artificial warming experiments were then used to measure the temperature at which common thermoregulatory behaviours are initiated and the subsequent reductions in body temperature. Behavioural means such as timing of activity, choice of substrates with optimum surface temperatures, shade seeking and postural adjustments (e.g. stilting, vertical orientation) were found to be highly effective at maintaining preferred body temperature. The maximum voluntarily tolerated temperature (MVT) was determined to be 44 °C ± 0.4 °C, indicating the upper bounds of thermal flexibility in this species. Behavioural thermoregulation effectively enables small ectotherms to regulate exposure to changing environmental temperatures and utilize the spatially and temporally heterogeneous environments they occupy. Species such as the wingless grasshopper, although adapted to cool temperate conditions, are likely to be well equipped to respond successfully to coarse scale climate change.

  4. The effectiveness of common thermo-regulatory behaviours in a cool temperate grasshopper.

    PubMed

    Harris, Rebecca M B; McQuillan, Peter; Hughes, Lesley

    2015-08-01

    Behavioural thermoregulation has the potential to alleviate the short-term impacts of climate change on some small ectotherms, without the need for changes to species distributions or genetic adaptation. We illustrate this by measuring the effect of behaviour in a cool temperate species of grasshopper (Phaulacridium vittatum) over a range of spatial and temporal scales in laboratory and natural field experiments. Microhabitat selection at the site scale was tested in free-ranging grasshoppers and related to changing thermal quality over a daily period. Artificial warming experiments were then used to measure the temperature at which common thermoregulatory behaviours are initiated and the subsequent reductions in body temperature. Behavioural means such as timing of activity, choice of substrates with optimum surface temperatures, shade seeking and postural adjustments (e.g. stilting, vertical orientation) were found to be highly effective at maintaining preferred body temperature. The maximum voluntarily tolerated temperature (MVT) was determined to be 44°C±0.4°C, indicating the upper bounds of thermal flexibility in this species. Behavioural thermoregulation effectively enables small ectotherms to regulate exposure to changing environmental temperatures and utilize the spatially and temporally heterogeneous environments they occupy. Species such as the wingless grasshopper, although adapted to cool temperate conditions, are likely to be well equipped to respond successfully to coarse scale climate change.

  5. Thermoregulatory responses during thermal acclimation in pigs divergently selected for residual feed intake

    NASA Astrophysics Data System (ADS)

    Campos, Paulo Henrique Reis Furtado; Noblet, Jean; Jaguelin-Peyraud, Yolande; Gilbert, Hélène; Mormède, Pierre; de Oliveira Donzele, Rita Flavia Miranda; Donzele, Juarez Lopes; Renaudeau, David

    2014-09-01

    The objective of this study was to evaluate the performance and thermoregulatory responses during acclimation to high ambient temperature (Ta) of pigs from two lines selected for high (RFI+) or low (RFI-) residual feed intake with the hypothesis that RFI- pigs producing less heat would better tolerate high Ta. Pigs (50 kg initial body weight; 17 per line among which 10 of them were catheterized) were individually housed in a climatic-controlled room where Ta was maintained at 24.2 ± 0.4 °C during 7 days and thereafter at 30.4 ± 0.7 °C during 14 days. Irrespective of Ta, RFI- pigs had lower feed intake (ADFI) and similar average daily gain (ADG) than RFI+ pigs. Whatever the line, ADFI, ADG, and feed efficiency decreased with increased Ta. Overall, the Ta increase resulted in an increase in rectal temperature (RT), skin temperature (ST), and respiratory rate (RR) within the first 24-48 h and, subsequently, in a decrease followed by stabilization. The RT decrease during acclimation occurred 24 h earlier in RFI- pigs than in RFI+. Thyroid hormones and cortisol decreased at high Ta and it was similar in both lines. Based on performance and RT, ST, and RR responses, it seems that selection for low RFI tends to ameliorate pigs' tolerance to high Ta. Nevertheless, this selection does not induce significant differences between lines in endocrine and metabolite responses during thermal stress.

  6. Thermoregulatory and Cardiovascular Consequences of a Transient Thyrotoxicosis and Recovery in Male Mice.

    PubMed

    Hoefig, Carolin S; Harder, Lisbeth; Oelkrug, Rebecca; Meusel, Moritz; Vennström, Björn; Brabant, Georg; Mittag, Jens

    2016-07-01

    Thyroid hormones play a major role in body homeostasis, regulating energy expenditure and cardiovascular function. Given that obese people or athletes might consider rapid weight loss as beneficial, voluntary intoxication with T4 preparations is a growing cause for thyrotoxicosis. However, the long-lasting effects of transient thyrotoxicosis are poorly understood. Here we examined metabolic, thermoregulatory, and cardiovascular function upon induction and recovery from a 2-week thyrotoxicosis in male C57BL/6J mice. Our results showed that T4 treatment caused tachycardia, decreased hepatic glycogen stores, and higher body temperature as expected; however, we did not observe an increase in brown fat thermogenesis or decreased tail heat loss, suggesting that these tissues do not contribute to the hyperthermia induced by thyroid hormone. Most interestingly, when the T4 treatment was ended, a pronounced bradycardia was observed in the animals, which was likely caused by a rapid decline of T3 even below baseline levels. On the molecular level, this was accompanied by an overexpression of cardiac phospholamban and Serca2a mRNA, supporting the hypothesis that the heart depends more on T3 than T4. Our findings therefore demonstrate that a transient thyrotoxicosis can have pathological effects that even persist beyond the recovery of serum T4 levels, and in particular the observed bradycardia could be of clinical relevance when treating hyperthyroid patients.

  7. Potentiation of thermoregulatory responses to isoproterenol by beta-adrenergic antagonists.

    PubMed

    Carlisle, H J; Stock, M J

    1992-10-01

    The thermoregulatory effects of isothermogenic doses of isoproterenol (Iso) and a novel beta-agonist (BRL 35135) were tested in rats at 22 degrees C and in rats trained to bar press for radiant heat at -8 degrees C. BRL 35135 produced hyperthermia at 22 degrees C and reduced operant responding for heat at -8 degrees C, whereas Iso reduced body temperature and increased operant responding. In both situations, the negative effects of Iso on thermal balance were abolished by propranolol at doses that did not inhibit heat production. In anesthetized rats, propranolol potentiated the Iso-induced rise in brown adipose tissue and colonic temperature. The potentiation was more marked with the beta 2-selective antagonist ICI 118,551, whereas treatment with the beta 1-selective antagonist atenolol resulted in a profound Iso-induced reduction in temperature. The two selective antagonists also produced divergent responses in operant behavior in Iso-treated rats at -8 degrees C. These experiments demonstrate the extent to which responses to a nonselective agonist can be manipulated using appropriately low doses of selective antagonists and indicate that the effects of Iso on thermal balance are due to its beta 2 activity.

  8. Effect of skin sympathetic response to local or systemic cold exposure on thermoregulatory functions in humans.

    PubMed

    Sawasaki, N; Iwase, S; Mano, T

    2001-03-23

    We studied how, sympathetic response to cold exposure determines thermoregulatory function. Three female and seven male volunteers (age, 23.2+/-1.9 years) were exposed to abrupt local cooling and gradual systemic cooling with recording of microneurographic skin sympathetic nerve activity tSSNA), skill temperatures (Ts), tympanic temperature (Tty), skin blood flow measured by laser Doppler flowmetry, and sweating rate measured with a ventilated capsule. Local cooling induced an abrupt vasoconstrictor SSNA increase and Tty rise. There was a significant positive correlation between the increase in the vasoconstrictor SSNA and the change rate of Tty. Systemic cooling at 0.2 degrees C/min enhanced SSNA but gradually decreased Tty, and a significant negative correlation was observed between them. A 10-min delay separated the SSNA rise from the subsequent Tty rise following local cooling. A delay of less than 1 min preceded the SSNA increase after the Tty fall induced by systemic cooling. These findings suggested that subjects with a good SSNA response to cold stress can maintain core temperature, but 10 min is necessary to raise the core temperature by reducing heat loss from the skin surface. In contrast. vasoconstrictor SSNA responds linearly to a fall in core temperature with a delay of less than 1 min.

  9. The Reliability of Adolescent Thermoregulatory Responses During a Heat Acclimation Protocol

    PubMed Central

    Brokenshire, Caroline S.; Armstrong, Neil; Williams, Craig A.

    2009-01-01

    This study investigated the between trial variation of thermoregulatory measures during a heat acclimation protocol. Eight 14-16 y old boys completed three bouts of 20-min cycling at 45 % peak VO2 in a hot environment (35.1 ± 1.2 °C and 46. 4 ± 1.0 % relative humidity) on two occasions separated by a minimum of 24 h. Reliability was assessed through analysis of within-subject variation, the change in the mean, and retest correlation for measurements of aural temperature (Tau), mean skin temperature (Tsk), heart rate (HR) and oxygen uptake (VO2). Between trial differences were low for Tau, Tskbout1, Tskbout2and3 and HR with coefficients of variation 0.6 %, 1.5 %, 0.5 % and 4.0 %, respectively. The results demonstrate good reliability that will allow future investigators to precisely determine the extent of heat acclimation protocols in relation to the measurement error. Key points To allow paediatric heat acclimation guidelines to be produced, the extent of heat acclimation needs to be established once biological and mechanical variation has been accounted for. The results of the present study indicate that between trial differences were low for aural temperature, mean skin temperature and heart rate with coefficient of variation values ranging from 0.6 - 4.0 %. Future investigators will be able to utilise the coefficient of variation values to establish the effectiveness of heat acclimation with precision alongside the selection of appropriate sample size. PMID:24149612

  10. An efficient and inexpensive method for measuring long-term thermoregulatory behavior

    PubMed Central

    Sperry, Jinelle H.; Rohr, Jason R.

    2016-01-01

    Thermoregulatory ability and behavior influence organismal responses to their environment. By measuring thermal preferences, researchers can better understand the effects that temperature tolerances have on ecological and physiological responses to both biotic and abiotic stressors. However, because of funding limitations and confounders, measuring thermoregulation can often be difficult. Here, we provide an effective, affordable (∼$50 USD per unit), easy to construct, and validated apparatus for measuring the long-term thermal preferences of animals. In tests, the apparatus spanned temperatures from 9.29 to 33.94 °C, and we provide methods to further increase this range. Additionally, we provide simple methods to non-invasively measure animal and substrate temperatures and to prevent temperature preferences of the focal organisms from being confounded with temperature preferences of its prey and its humidity preferences. To validate the apparatus, we show that it was capable of detecting individual-level consistency and among individual-level variation in the preferred body temperatures of Southern toads (Anaxyrus terrestris) and Cuban tree frogs (Osteopilus septentrionalis) over three-weeks. Nearly every aspect of our design is adaptable to meet the needs of a multitude of study systems, including various terrestrial amphibious, and aquatic organisms. The apparatus and methods described here can be used to quantify behavioral thermal preferences, which can be critical for determining temperature tolerances across species and thus the resiliency of species to current and impending climate change. PMID:27503737

  11. Thermoregulatory changes induced by cholinomimetic substances introduced into the cerebral ventricles of sheep.

    PubMed Central

    Johnson, K G

    1975-01-01

    1 Thermoregulatory responses have been recorded from Welsh Mountain sheep exposed to warm, neutral or cold environments while injections of cholinomimetic drugs and/or their antagonists have been given into a lateral cerebral ventricle. 2. Carbachol and physostigmine inhibited panting of animals at high ambient temperature (ta), caused vasoconstriction and initiated shivering at neutral ta, and accentuated shivering at low ta. Rectal temperature (tre) invariably increased. Oxotremorine had apparently identical effects. 3. Nicotine and another ganglionic stimulant, the quaternary methyl derivative of dopamine, had no effects on thermoregulation. 4.Atropine given 10 min before injections of carbachol, physostigmine or oxotremorine completely inhibited their hyperthermic effects, but pretreatment with the ganglion-blocking drug, pempidine, caused no inhibition. The cholinergic synapses that respond to cholinomimetic drugs injected into the lateral cerebral ventricles of sheep are therefore muscarinic and not nicotinic. 5. When atropine was given to sheep exposed to cold, no detectable reduction of shivering occurred and tre decreased only slightly, even with doses of atropine far greater than needed to inhibit shivering induced by physostigmine. This may be because shivering is controlled by neural pathways unaffected by drugs administered intracerebroventricularly or because the cholinergic synapses activated by physostigmine do not carry the input from cold sensors. PMID:1148492

  12. Octopamine and tyramine modulate the thermoregulatory fanning response in honey bees (Apis mellifera L.).

    PubMed

    Cook, Chelsea N; Brent, Colin S; Breed, Michael D

    2017-03-17

    Biogenic amines regulate the proximate mechanisms underlying most behavior, including those that contribute to the overall success of complex societies. For honey bees, one critical set of behaviors contributing to the welfare of a colony is involved with nest thermoregulation. Worker honeybees cool the colony by performing a fanning behavior, the expression of which is largely influenced by response thresholds modulated by the social environment. Here, we examined how changes in biogenic amines affect this group-performed thermoregulatory fanning behavior in honeybees. Concentrations of two biogenic amines, octopamine and tyramine, are significantly lower in active fanners than in non-fanners, but there is no difference in dopamine and serotonin. Direct feeding of octopamine and tyramine induced a decrease in fanning responses, but only when both amines were included in the treatment. This is the first evidence that fanning behavior is influenced by these two biogenic amines, and this result is consistent with the typical role of these neurotransmitters in regulating locomotor activity in other insects. Individual variation in amine expression also provides a mechanistic link that helps to explain how this group behavior might be coordinated within a colony.

  13. Experimental and failure analysis of the prosthetic finger joint implants

    NASA Astrophysics Data System (ADS)

    Naidu, Sanjiv H.

    Small joint replacement arthroplasty of the hand is a well accepted surgical procedure to restore function and cosmesis in an individual with a crippled hand. Silicone elastomers have been used as prosthetic material in various small hand joints for well over three decades. Although the clinical science aspects of silicone elastomer failure are well known, the physical science aspects of prosthetic failure are scant and vague. In the following thesis, using both an animal model, and actual retrieved specimens which have failed in human service, experimental and failure analysis of silicone finger joints are presented. Fractured surfaces of retrieved silicone trapezial implants, and silicone finger joint implants were studied with both FESEM and SEM; the mode of failure for silicone trapezium is by wear polishing, whereas the finger joint implants failed either by fatigue fracture or tearing of the elastomer, or a combination of both. Thermal analysis revealed that the retrieved elastomer implants maintained its viscoelastic properties throughout the service period. In order to provide for a more functional and physiologic arthroplasty a novel finger joint (Rolamite prosthesis) is proposed using more recently developed thermoplastic polymers. The following thesis also addresses the outcome of the experimental studies of the Rolamite prosthesis in a rabbit animal model, in addition to the failure analysis of the thermoplastic polymers while in service in an in vivo synovial environment. Results of retrieved Rolamite specimens suggest that the use for thermoplastic elastomers such as block copolymer based elastomers in a synovial environment such as a mammalian joint may very well be limited.

  14. Context-dependent DNA recognition code for C2H2 zinc-finger transcription factors

    PubMed Central

    Liu, Jiajian; Stormo, Gary D.

    2008-01-01

    Motivation: Modeling and identifying the DNA-protein recognition code is one of the most challenging problems in computational biology. Several quantitative methods have been developed to model DNA-protein interactions with specific focus on the C2H2 zinc-finger proteins, the largest transcription factor family in eukaryotic genomes. In many cases, they performed well. But the overall the predictive accuracy of these methods is still limited. One of the major reasons is all these methods used weight matrix models to represent DNA-protein interactions, assuming all base-amino acid contacts contribute independently to the total free energy of binding. Results: We present a context-dependent model for DNA–zinc-finger protein interactions that allows us to identify inter-positional dependencies in the DNA recognition code for C2H2 zinc-finger proteins. The degree of non-independence was detected by comparing the linear perceptron model with the non-linear neural net (NN) model for their predictions of DNA–zinc-finger protein interactions. This dependency is supported by the complex base-amino acid contacts observed in DNA–zinc-finger interactions from structural analyses. Using extensive published qualitative and quantitative experimental data, we demonstrated that the context-dependent model developed in this study can significantly improves predictions of DNA binding profiles and free energies of binding for both individual zinc fingers and proteins with multiple zinc fingers when comparing to previous positional-independent models. This approach can be extended to other protein families with complex base-amino acid residue interactions that would help to further understand the transcriptional regulation in eukaryotic genomes. Availability:The software implemented as c programs and are available by request. http://ural.wustl.edu/softwares.html Contact: stormo@ural.wustl.edu PMID:18586699

  15. Influence of ambient temperature on the thermoregulatory responses to 5-hydroxytryptamine, noradrenaline and acetylcholine injected into the lateral cerebral ventricles of sheep, goats and rabbits

    PubMed Central

    Bligh, J.; Cottle, W. H.; Maskrey, M.

    1971-01-01

    1. The influences of ambient temperature (Ta) on the thermoregulatory effector activities and the body temperature (Tb) of intraventricular injections into the sheep, goat and rabbit of 5-hydroxytryptamine (5-HT), noradrenaline (NA), acetylcholine (ACh), carbachol and eserine, have been interpreted in terms of a simple neuronal model of the pathways between thermosensors and thermoregulatory effectors. 2. In all three species 5-HT in minimal doses caused a rise in respiratory frequency (RF) and a fall in Tb at high Ta, and a reduction in EMG activity and a fall in Tb at low Ta. These effects could be interpreted as those of an excitatory transmitter acting on the warm receptor—heat loss pathway. 3. In all three species NA caused a reduction in RF and a rise in Tb at high Ta, and a reduction in EMG activity and a fall in Tb at low Ta. These effects are interpreted as those of an inhibitory transmitter acting both on the warm sensor—heat loss pathways and on the cold sensor—heat production pathway. 4. The effects of ACh and the cholinomimetic substances carbachol and eserine are complex and more difficult to interpret. In small doses the effects on the sheep and goat are those of an excitatory transmitter on the cold sensor—heat production pathway. There was an increase in EMG activity and a rise in Tb at low Ta, and a reduction in RF and a rise in Tb at high Ta. At higher dose levels in the goat and at all dose levels in the rabbit these substances had the reverse effects which are attributed to a synaptic block due to the excess of the excitatory substance. 5. The effects of ambient temperature and injected substances upon ear temperature are consistent with the predictions of the model if it is assumed (a) that at high and low ambient temperatures direct thermal effects on ear vessels dominate those of the sympathetic innervation, and (b) that the warm sensor influence is to lower peripheral vasomotor tone, and the cold sensor influence is to increase it

  16. Detection and classification of multiple finger movements using a chronically implanted Utah Electrode Array.

    PubMed

    Egan, Joshua; Baker, Justin; House, Paul; Greger, Bradley

    2011-01-01

    The ability to detect and classify individual and combined finger movements from neural data is rapidly advancing. The work that has been done has demonstrated the feasibility of decoding finger movements from acutely recorded neurons. There is a need for a recording model that meets the chronic requirements of a neuroprosthetic application and to address this need we have developed an algorithm that can detect and classify individual and combined finger movements using neuronal data acquired from a chronically implanted Utah Electrode Array (UEA). The algorithm utilized the firing rates of individual neurons and performed with an average sensitivity and an average specificity that were both greater than 92% across all movement types. These results lend further support that a chronically implanted UEA is suitable for acquiring and decoding neuronal data and also demonstrate a decoding method that can detect and classify finger movements without any a priori knowledge of the data, task, or behavior.

  17. Radial fingering at an active interface

    NASA Astrophysics Data System (ADS)

    Nagilla, Amarender; Prabhakar, Ranganathan; Jadhav, Sameer

    2016-11-01

    It has been suggested that the shapes of single cells crawling on surfaces and those of the fronts of thin layers of cells collectively expanding to close a wound are the results of fingering instabilities. Motivated by these studies, we investigate the conditions under which an actively forced interface between a pair of immiscible viscous fluids will destabilize under Hele-Shaw confinement. The case of a circular active interface with surface tension and bending resistance is considered. Active forces exerted by the inner fluid at the interfacial region can be either completely internal or due to interactions with the confining substrate. In addition, the effects of cell growth or actin depolymerization or external injection of cell suspensions are modeled by including a distributed source and a point source of arbitrary strengths. Linear stability analysis reveals that at any given mean radius of the interface, its stability is dictated by two key dimensionless parameters. We discuss the different regions in a state space of these parameters.

  18. Ultrafast High-Resolution Mass Spectrometric Finger Pore Imaging in Latent Finger Prints

    NASA Astrophysics Data System (ADS)

    Elsner, Christian; Abel, Bernd

    2014-11-01

    Latent finger prints (LFPs) are deposits of sweat components in ridge and groove patterns, left after human fingers contact with a surface. Being important targets in biometry and forensic investigations they contain more information than topological patterns. With laser desorption mass spectrometry imaging (LD-MSI) we record `three-dimensional' finger prints with additional chemical information as the third dimension. Here we show the potential of fast finger pore imaging (FPI) in latent finger prints employing LD-MSI without a classical matrix in a high- spatial resolution mode. Thin films of gold rapidly sputtered on top of the sample are used for desorption. FPI employing an optical image for rapid spatial orientation and guiding of the desorption laser enables the rapid analysis of individual finger pores, and the chemical composition of their excretions. With this approach we rapidly detect metabolites, drugs, and characteristic excretions from the inside of the human organism by a minimally-invasive strategy, and distinguish them from chemicals in contact with fingers without any labeling. The fast finger pore imaging, analysis, and screening approach opens the door for a vast number of novel applications in such different fields as forensics, doping and medication control, therapy, as well as rapid profiling of individuals.

  19. Ultrafast High-Resolution Mass Spectrometric Finger Pore Imaging in Latent Finger Prints

    PubMed Central

    Elsner, Christian; Abel, Bernd

    2014-01-01

    Latent finger prints (LFPs) are deposits of sweat components in ridge and groove patterns, left after human fingers contact with a surface. Being important targets in biometry and forensic investigations they contain more information than topological patterns. With laser desorption mass spectrometry imaging (LD-MSI) we record ‘three-dimensional' finger prints with additional chemical information as the third dimension. Here we show the potential of fast finger pore imaging (FPI) in latent finger prints employing LD-MSI without a classical matrix in a high- spatial resolution mode. Thin films of gold rapidly sputtered on top of the sample are used for desorption. FPI employing an optical image for rapid spatial orientation and guiding of the desorption laser enables the rapid analysis of individual finger pores, and the chemical composition of their excretions. With this approach we rapidly detect metabolites, drugs, and characteristic excretions from the inside of the human organism by a minimally-invasive strategy, and distinguish them from chemicals in contact with fingers without any labeling. The fast finger pore imaging, analysis, and screening approach opens the door for a vast number of novel applications in such different fields as forensics, doping and medication control, therapy, as well as rapid profiling of individuals. PMID:25366032

  20. Design and preliminary evaluation of the FINGER rehabilitation robot: controlling challenge and quantifying finger individuation during musical computer game play

    PubMed Central

    2014-01-01

    Background This paper describes the design and preliminary testing of FINGER (Finger Individuating Grasp Exercise Robot), a device for assisting in finger rehabilitation after neurologic injury. We developed FINGER to assist stroke patients in moving their fingers individually in a naturalistic curling motion while playing a game similar to Guitar Hero®a. The goal was to make FINGER capable of assisting with motions where precise timing is important. Methods FINGER consists of a pair of stacked single degree-of-freedom 8-bar mechanisms, one for the index and one for the middle finger. Each 8-bar mechanism was designed to control the angle and position of the proximal phalanx and the position of the middle phalanx. Target positions for the mechanism optimization were determined from trajectory data collected from 7 healthy subjects using color-based motion capture. The resulting robotic device was built to accommodate multiple finger sizes and finger-to-finger widths. For initial evaluation, we asked individuals with a stroke (n = 16) and without impairment (n = 4) to play a game similar to Guitar Hero® while connected to FINGER. Results Precision design, low friction bearings, and separate high speed linear actuators allowed FINGER to individually actuate the fingers with a high bandwidth of control (−3 dB at approximately 8 Hz). During the tests, we were able to modulate the subject’s success rate at the game by automatically adjusting the controller gains of FINGER. We also used FINGER to measure subjects’ effort and finger individuation while playing the game. Conclusions Test results demonstrate the ability of FINGER to motivate subjects with an engaging game environment that challenges individuated control of the fingers, automatically control assistance levels, and quantify finger individuation after stroke. PMID:24495432

  1. Hypermobility and proprioception in the finger joints of flautists.

    PubMed

    Artigues-Cano, Isabel; Bird, Howard A

    2014-06-01

    Ergonomically, the flute is especially complex among wind instruments, and flautists may therefore be at particular risk of performance-related musculoskeletal disorders. Yet little is known about injury prevalence among flute players, and even less in those flautists who are also hypermobile. Recent research has found hand and wrist pain to be common complaints among flautists. Understanding of the predictors of injury and pain is therefore crucial as the presence of pain decreases performance quality and causes unnecessary time loss. There is a strong relationship between hypermobility and impaired proprioception, although many musicians may acquire greater proprioception than the average population. We have compared flexibility and proprioception of the hand in a study of flautists. Twenty flautists took part in the study. General hypermobility, the passive range of motion of the 3 specific joints most involved in flute playing, and proprioception acuity were all measured accurately for the first time in this awkward instrument that needs high levels of dexterity. Flautists' finger joints have a greater range of movement than in the general population. This group of flute players had especially large ranges of movement in the finger joints, which take the weight of the instrument. Although flautists have hypermobile finger joints, they are not generally hypermobile elsewhere as measured by the Beighton Scale. Flautists, even with very mobile finger joints, have very accurate proprioception, which may be acquired through training. The study of instrumentalists may provide an ideal model for study of the interaction between localized joint flexibility and joint proprioception, both inherited and acquired.

  2. Finger pad friction and its role in grip and touch.

    PubMed

    Adams, Michael J; Johnson, Simon A; Lefèvre, Philippe; Lévesque, Vincent; Hayward, Vincent; André, Thibaut; Thonnard, Jean-Louis

    2013-03-06

    Many aspects of both grip function and tactile perception depend on complex frictional interactions occurring in the contact zone of the finger pad, which is the subject of the current review. While it is well established that friction plays a crucial role in grip function, its exact contribution for discriminatory touch involving the sliding of a finger pad is more elusive. For texture discrimination, it is clear that vibrotaction plays an important role in the discriminatory mechanisms. Among other factors, friction impacts the nature of the vibrations generated by the relative movement of the fingertip skin against a probed object. Friction also has a major influence on the perceived tactile pleasantness of a surface. The contact mechanics of a finger pad is governed by the fingerprint ridges and the sweat that is exuded from pores located on these ridges. Counterintuitively, the coefficient of friction can increase by an order of magnitude in a period of tens of seconds when in contact with an impermeably smooth surface, such as glass. In contrast, the value will decrease for a porous surface, such as paper. The increase in friction is attributed to an occlusion mechanism and can be described by first-order kinetics. Surprisingly, the sensitivity of the coefficient of friction to the normal load and sliding velocity is comparatively of second order, yet these dependencies provide the main basis of theoretical models which, to-date, largely ignore the time evolution of the frictional dynamics. One well-known effect on taction is the possibility of inducing stick-slip if the friction decreases with increasing sliding velocity. Moreover, the initial slip of a finger pad occurs by the propagation of an annulus of failure from the perimeter of the contact zone and this phenomenon could be important in tactile perception and grip function.

  3. Finger pad friction and its role in grip and touch

    PubMed Central

    Adams, Michael J.; Johnson, Simon A.; Lefèvre, Philippe; Lévesque, Vincent; Hayward, Vincent; André, Thibaut; Thonnard, Jean-Louis

    2013-01-01

    Many aspects of both grip function and tactile perception depend on complex frictional interactions occurring in the contact zone of the finger pad, which is the subject of the current review. While it is well established that friction plays a crucial role in grip function, its exact contribution for discriminatory touch involving the sliding of a finger pad is more elusive. For texture discrimination, it is clear that vibrotaction plays an important role in the discriminatory mechanisms. Among other factors, friction impacts the nature of the vibrations generated by the relative movement of the fingertip skin against a probed object. Friction also has a major influence on the perceived tactile pleasantness of a surface. The contact mechanics of a finger pad is governed by the fingerprint ridges and the sweat that is exuded from pores located on these ridges. Counterintuitively, the coefficient of friction can increase by an order of magnitude in a period of tens of seconds when in contact with an impermeably smooth surface, such as glass. In contrast, the value will decrease for a porous surface, such as paper. The increase in friction is attributed to an occlusion mechanism and can be described by first-order kinetics. Surprisingly, the sensitivity of the coefficient of friction to the normal load and sliding velocity is comparatively of second order, yet these dependencies provide the main basis of theoretical models which, to-date, largely ignore the time evolution of the frictional dynamics. One well-known effect on taction is the possibility of inducing stick–slip if the friction decreases with increasing sliding velocity. Moreover, the initial slip of a finger pad occurs by the propagation of an annulus of failure from the perimeter of the contact zone and this phenomenon could be important in tactile perception and grip function. PMID:23256185

  4. Perceiving fingers in single-digit arithmetic problems

    PubMed Central

    Berteletti, Ilaria; Booth, James R.

    2015-01-01

    In this study, we investigate in children the neural underpinnings of finger representation and finger movement involved in single-digit arithmetic problems. Evidence suggests that finger representation and finger-based strategies play an important role in learning and understanding arithmetic. Because different operations rely on different networks, we compared activation for subtraction and multiplication problems in independently localized finger somatosensory and motor areas and tested whether activation was related to skill. Brain activations from children between 8 and 13 years of age revealed that only subtraction problems significantly activated finger motor areas, suggesting reliance on finger-based strategies. In addition, larger subtraction problems yielded greater somatosensory activation than smaller problems, suggesting a greater reliance on finger representation for larger numerical values. Interestingly, better performance in subtraction problems was associated with lower activation in the finger somatosensory area. Our results support the importance of fine-grained finger representation in arithmetical skill and are the first neurological evidence for a functional role of the somatosensory finger area in proficient arithmetical problem solving, in particular for those problems requiring quantity manipulation. From an educational perspective, these results encourage investigating whether different finger-based strategies facilitate arithmetical understanding and encourage educational practices aiming at integrating finger representation and finger-based strategies as a tool for instilling stronger numerical sense. PMID:25852582

  5. Blood pressure measurement using finger cuff.

    PubMed

    Lee, J; Choi, E; Jeong, H; Kim, K; Park, J

    2005-01-01

    Many research groups have studied blood pressure measurement in finger artery because of its convenience. But, low accuracy prohibits many hypertension patients from using this device. So, we suggest measurement algorithm that measure systolic and diastolic blood pressure in finger artery. And we also develop calibration method that decreases the error from difference of finger circumference by subjects. We apply our methods for 90 subjects (age form 20 to 49, 55 male, 35 female) to test feasibility of our method by AAMI SP10 standard. The mean difference of our system is ±4.7mmHg for systolic pressure, ±4.2mmHg for systolic pressure. It proved that the feasibility of our method is clinically acceptable.(under ±5mmHg).

  6. [Breeding of robust industrial ethanol-tolerant Saccharomyces cerevisiae strain by artificial zinc finger protein library].

    PubMed

    Ma, Cui; Zhao, Xinqing; Li, Qian; Zhang, Mingming; Kim, Jin Soo; Bai, Fengwu

    2013-05-01

    Breeding of robust industrial Saccharomyces cerevisiae strains with high ethanol tolerance is of great significance for efficient fuel ethanol production. Zinc finger proteins play important roles in gene transcription and translation, and exerting control on the regulation of multiple genes. The sequence and localization of the zinc finger motif can be designed and engineered, and the artificial zinc finger protein can be used to regulate celluar metabolism. Stress tolerance of microbial strains is related to multiple genes. Therefore, it is possible to use artificially-designed zinc finger proteins to breed stress tolerant strains. In this study, a library containing artificial zinc finger protein encoding genes was transformed into the model yeast strain S288c. A recombinant strain named M01 with improved ethanol tolerance was obtained. The plasmid in M01 was isolated, and then transformed into the industrial yeast strain Sc4126. Ethanol tolerance of the recombinant strain of Sc4126 were significantly improved. When high gravity ethanol fermentation using 250 g/L glucose was performed, comparing with the wild-type strain, fermentation time of the recombinant strain was decreased by 24 h and the final ethanol concentration was enhanced by 6.3%. The results of this study demonstrate that artificial zinc finger proteins are able to exert control on stress tolerance of yeast strains, and these results provide basis to construct robust industrial yeast strains for efficient ethanol fermentation.

  7. Finger forces in fastball baseball pitching.

    PubMed

    Kinoshita, Hiroshi; Obata, Satoshi; Nasu, Daiki; Kadota, Koji; Matsuo, Tomoyuki; Fleisig, Glenn S

    2017-08-01

    Forces imparted by the fingers onto a baseball are the final, critical aspects for pitching, however these forces have not been quantified previously as no biomechanical technology was available. In this study, an instrumented baseball was developed for direct measurement of ball reaction force by individual fingers and used to provide fundamental information on the forces during a fastball pitch. A tri-axial force transducer with a cable having an easily-detachable connector were installed in an official baseball. Data were collected from 11 pitchers who placed the fingertip of their index, middle, ring, or thumb on the transducer, and threw four-seam fastballs to a target cage from a flat mound. For the index and middle fingers, resultant ball reaction force exhibited a bimodal pattern with initial and second peaks at 38-39ms and 6-7ms before ball release, and their amplitudes were around 97N each. The ring finger and thumb produced single-peak forces of approximately 50 and 83N, respectively. Shear forces for the index and middle fingers formed distinct peak at 4-5ms before release, and the peaks summed to 102N; a kinetic source for backspin on the ball. An additional experiment with submaximal pitching effort showed a linear relationship of peak forces with ball velocity. The peak ball reaction force for fastballs exceeded 80% of maximum finger strength measured, suggesting that strengthening of the distal muscles is important both for enhancing performance and for avoiding injuries. Copyright © 2017 Elsevier B.V. All rights reserved.

  8. Finger recognition and gesture imitation in Gerstmann's syndrome.

    PubMed

    Moro, V; Pernigo, S; Urgesi, C; Zapparoli, P; Aglioti, S M

    2008-01-01

    We report the association between finger agnosia and gesture imitation deficits in a right-handed, right-hemisphere damaged patient with Gerstmann's syndrome (GS), a neuropsychological syndrome characterized by finger and toe agnosia, left-right disorientation and dyscalculia. No language deficits were found. The patient showed a gestural imitation deficit that specifically involved finger movements and postures. The association between finger recognition and imitation deficits suggests that both static and dynamic aspects of finger representations are impaired in GS. We suggest that GS is a disorder of body representation that involves hands and fingers, that is, the non-facial body parts most involved in social interactions.

  9. Effects of isotonic and isometric exercises with mist sauna bathing on cardiovascular, thermoregulatory, and metabolic functions

    NASA Astrophysics Data System (ADS)

    Iwase, Satoshi; Kawahara, Yuko; Nishimura, Naoki; Nishimura, Rumiko; Sugenoya, Junichi; Miwa, Chihiro; Takada, Masumi

    2014-08-01

    To clarify the effects of isometric and isotonic exercise during mist sauna bathing on the cardiovascular function, thermoregulatory function, and metabolism, six healthy young men (22 ± 1 years old, height 173 ± 4 cm, weight 65.0 ± 5.0 kg) were exposed to a mist sauna for 10 min at a temperature of 40 °C, and relative humidity of 100 % while performing or not performing ˜30 W of isometric or isotonic exercise. The effect of the exercise was assessed by measuring tympanic temperature, heart rate, systolic and diastolic blood pressure, chest sweat rate, chest skin blood flow, and plasma catecholamine and cortisol, glucose, lactate, and free fatty acid levels. Repeated measures ANOVA showed no significant differences in blood pressure, skin blood flow, sweat rate, and total amount of sweating. Tympanic temperature increased more during isotonic exercise, and heart rate increase was more marked during isotonic exercise. The changes in lactate indicated that fatigue was not very great during isometric exercise. The glucose level indicated greater energy expenditure during isometric exercise. The free fatty acid and catecholamine levels indicated that isometric exercise did not result in very great energy expenditure and stress, respectively. The results for isotonic exercise of a decrease in lactate level and an increase in plasma free fatty acid level indicated that fatigue and energy expenditure were rather large while the perceived stress was comparatively low. We concluded that isotonic exercise may be a more desirable form of exercise during mist sauna bathing given the changes in glucose and free fatty acid levels.

  10. Effect of stride frequency on thermoregulatory responses during endurance running in distance runners.

    PubMed

    Amano, Tatsuro; Ishitobi, Masaki; Ogura, Yukio; Inoue, Yoshimitsu; Koga, Shunsaku; Nishiyasu, Takeshi; Kondo, Narihiko

    2016-10-01

    Changing stride frequency may influence oxygen uptake and heart rate during running as a function of running economy and central command. This study investigated the influence of stride frequency manipulation on thermoregulatory responses during endurance running. Seven healthy endurance runners ran on a treadmill at a velocity of 15km/h for 60min in a controlled environmental chamber (ambient temperature 27°C and relative humidity 50%), and stride frequency was manipulated. Stride frequency was intermittently manipulated by increasing and decreasing frequency by 10% from the pre-determined preferred frequency. These periods of increase or decrease were separated by free frequency running in the order of free stride frequency, stride frequency manipulation (increase or decrease), free stride frequency, and stride frequency manipulation (increase or decrease) for 15min each. The increased and decreased stride frequencies were 110% and 91% of the free running frequency, respectively (196±6, 162±5, and 178±5steps/min, respectively, P<0.01). Compared to the control, stride frequency manipulation did not affect rectal temperature, heart rate, or the rate of perceived exhaustion during running. Whole-body sweat loss increased significantly when stride frequency was manipulated (1.48±0.11 and 1.57±0.11kg for control and manipulated stride frequencies, respectively, P<0.05), but stride frequency had a small effect on sweat loss overall (Cohen's d=0.31). A higher mean skin temperature was also observed under mixed frequency conditions compared to that in the control (P<0.05). While the precise mechanisms underlying these changes remain unknown (e.g. running economy or central command), our results suggest that manipulation of stride frequency does not have a large effect on sweat loss or other physiological variables, but does increase mean skin temperature during endurance running.

  11. Pressure and coverage effects of sporting compression garments on cardiovascular function, thermoregulatory function, and exercise performance.

    PubMed

    MacRae, Braid A; Laing, Raechel M; Niven, Brian E; Cotter, James D

    2012-05-01

    Sporting compression garments (CG) are used widely during exercise despite little evidence of benefits. The purpose of this study was to investigate coverage and pressure effects of full-body CG on cardiovascular and thermoregulatory function at rest and during prolonged exercise, and on exercise performance. Twelve recreationally trained male cyclists [mean (SD) age, 26 (7) years; VO(2 max), 53 (8) mL kg(-1) min(-1)] completed three sessions (counterbalanced order), wearing either correctly-sized CG (CSG; 11-15 mmHg), over-sized CG (OSG; 8-13 mmHg), or gym shorts (CONT). Test sessions were conducted in temperate conditions [24 (1)°C, 60 (4)% relative humidity; ~2 m s(-1) air velocity during exercise], consisting of resting on a chair then on a cycle ergometer, before 60-min fixed-load cycling at ~65% VO(2 max) and a 6-km time trial. Wearing CG (CSG or OSG) did not mitigate cardiovascular strain during mild orthostatic stress at rest (p = 0.20-0.93 for garment effects). During exercise, cardiac output was ~5% higher in the CG conditions (p < 0.05), which appears to be accounted for via non-significant higher end-exercise heart rate (~4-7%, p = 0.30; p = 0.06 for greater heart rate drift in CSG); other cardiovascular variables, including stroke volume, were similar among conditions (p = 0.23-0.91). Covered-skin temperature was higher in CG conditions (p < 0.001) but core (oesophageal) temperature was not (p = 0.79). Time-trial performance (mean power, time taken) was similar with or without CG (p = 0.24-0.44). In conclusion, any demonstrable physiological or psychophysical effects of full-body CG were mild and seemingly reflective more of surface coverage than pressure. No benefit was evident for exercise performance.

  12. Human thermoregulatory responses during cold-water immersion after artificially-induced sunburn

    SciTech Connect

    Pandolf, K.B.; Gange, R.W.; Latzka, W.A.; Blank, I.H.; Young, A.J.; Sawka, M.N. Massachusetts General Hospital, Boston )

    1991-03-11

    Thermoregulatory responses during cold-water immersion (T{sub w} = 22C) were compared in 10 men prior to artificially-induced sunburn (CONB), as well as 24-h, and 1-wk after a 2 minimal erythemal dose of UV-B radiation (SUNB) which covered {approximately}85% of the body. After 10 min of rest in cold water, these men exercised for 50 min ({approximately}51% {dot V}O{sub 2}max). Esophageal (T{sub es}), rectal (T{sub re}), and mean skin ({bar T}{sub sk}) temperatures, mean heat flow ({bar h}{sub c}), and heart rate (HR) were measured. Venous blood samples were collected before and after immersion. The {bar T}{sub sk} was higher throughout the 60-min immersion both 24-h and 1-wk after SUNB compared to CONB. The {anti h}{sub c} was higher after 10 min resting immersion and during the first 10 min of exercise when 24-h SUNB waqs compared to CONB with the difference attributed to higher h{sub c} from the back and chest. While T{sub re} and HR did not differ between conditions, T{sub es} prior to and throughout the 60-min immersion was higher when 24-h SUNB was compared to CONB. Plasma volume increased after 1-wk SUNB compared to CONB while plasma protein was reduced. Post-exercise cortisol was greater 24-h SUNB compared to either CONB or 1-wk SUNB. In conclusion, sunburn impaired the ability of these men to vasoconstrict during cold-water immersion resulting in greater heat loss. These adverse effects were still present 1 wk after sunburn when the associated erythema had disappeared.

  13. Effects of isotonic and isometric exercises with mist sauna bathing on cardiovascular, thermoregulatory, and metabolic functions.

    PubMed

    Iwase, Satoshi; Kawahara, Yuko; Nishimura, Naoki; Nishimura, Rumiko; Sugenoya, Junichi; Miwa, Chihiro; Takada, Masumi

    2014-08-01

    To clarify the effects of isometric and isotonic exercise during mist sauna bathing on the cardiovascular function, thermoregulatory function, and metabolism, six healthy young men (22 ± 1 years old, height 173 ± 4 cm, weight 65.0 ± 5.0 kg) were exposed to a mist sauna for 10 min at a temperature of 40 °C, and relative humidity of 100 % while performing or not performing ∼30 W of isometric or isotonic exercise. The effect of the exercise was assessed by measuring tympanic temperature, heart rate, systolic and diastolic blood pressure, chest sweat rate, chest skin blood flow, and plasma catecholamine and cortisol, glucose, lactate, and free fatty acid levels. Repeated measures ANOVA showed no significant differences in blood pressure, skin blood flow, sweat rate, and total amount of sweating. Tympanic temperature increased more during isotonic exercise, and heart rate increase was more marked during isotonic exercise. The changes in lactate indicated that fatigue was not very great during isometric exercise. The glucose level indicated greater energy expenditure during isometric exercise. The free fatty acid and catecholamine levels indicated that isometric exercise did not result in very great energy expenditure and stress, respectively. The results for isotonic exercise of a decrease in lactate level and an increase in plasma free fatty acid level indicated that fatigue and energy expenditure were rather large while the perceived stress was comparatively low. We concluded that isotonic exercise may be a more desirable form of exercise during mist sauna bathing given the changes in glucose and free fatty acid levels.

  14. Finger tapping in musicians and nonmusicians.

    PubMed

    Franĕk, M; Mates, J; Radil, T; Beck, K; Pöppel, E

    1991-12-01

    Timing plays an important role in perceiving and performing music. Finger tapping has been successfully used for analyzing timing processes (Fraisse, 1966, Franĕk et al., 1987, 1988). The aim of this study is to determine differences between musically trained and untrained subjects in their ability to follow repetitive rhythmic tonal patterns by finger tapping. It has been found previously (Povel, 1981; Smith, 1983) that time estimation differs among musicians and nonmusicians under certain conditions. The results presented here show that motor timing revealed by tapping is more accurate in musicians than in nonmusicians.

  15. Fluctuation of biological rhythm in finger tapping

    NASA Astrophysics Data System (ADS)

    Yoshinaga, H.; Miyazima, S.; Mitake, S.

    2000-06-01

    By analyzing biological rhythms obtained from finger tapping, we have investigated the differences of two biological rhythms between healthy and handicapped persons caused by Parkinson, brain infraction, car accident and so on. In this study, we have observed the motion of handedness of all subjects and obtained a slope a which characterizes a power-law relation between frequency and amplitude of finger-tapping rhythm. From our results, we have estimated that the slope a=0.06 is a rough criterion in order to distinguish healthy and handicapped persons.

  16. Density fingering of an exothermic autocatalytic reaction.

    PubMed

    Bánsági, T; Horváth, D; Tóth, A; Yang, J; Kalliadasis, S; De Wit, A

    2003-11-01

    Density fingering of exothermic autocatalytic fronts in vertically oriented porous media and Hele-Shaw cells is studied theoretically for chemical reactions where the solutal and thermal contribution to density changes have opposite signs. The competition between these two effects leads to thermal plumes for ascending fronts. The descending fronts behave strikingly differently as they can feature, for some values of the parameters, fingers of constant amplitude and wavelength. The differences between up and down going fronts are discussed in terms of dispersion curves and nonlinear dynamics. The theoretically predicted dispersion curves are experimentally evidenced with the chlorite-tetrathionate reaction.

  17. Solitary plasmacytoma of the index finger.

    PubMed

    Daneshbod, Yahya; Nowshadi, Pooria Ali; Negahban, Shahrzad; Aledavood, Azita; Ramzi, Mani; Fanaie, Sara; Bedayat, Gholamreza; Medeiros, L Jeffrey

    2014-09-01

    Solitary osseous plasmacytoma rarely involves the distal extremities. We report a case and provide a brief review of the relevant literature. We report a 64-year-old man who presented with swelling, mild pain and a deformed right index finger. The workup led to the diagnosis of solitary osseous plasmacytoma and the patient eventually required amputation of his finger. With clinical follow-up, the disease spread to regional lymph nodes and subsequently the patient developed systemic involvement and received chemotherapy. Solitary osseous plasmacytoma should be considered in the differential diagnosis of distal extremity neoplasms.

  18. Simulation of a cold-stressed finger including the effects of wind, gloves, and cold-induced vasodilatation.

    PubMed

    Shitzer, A; Bellomo, S; Stroschein, L A; Gonzalez, R R; Pandolf, K B

    1998-06-01

    The thermal response of fingers exposed to cold weather conditions has been simulated. Energy balance equations were formulated, in a former study, for the tissue layers and the arterial, venous, and capillary blood vessels. The equations were solved by a finite difference scheme using the Thomas algorithm and the method of alternating directions. At this stage of development the model does not include any autonomic control functions. Model simulations assumed an electrical heating element to be embedded in the glove layers applied on the finger. A 1.3 W power input was calculated for maintaining finger temperatures at their pre-cold exposure level in a 0 degree C environment. Alternate assumptions of nutritional (low) and basal (high) blood flows in the finger demonstrated the dominance of this factor in maintaining finger temperatures at comfortable levels. Simulated exposures to still and windy air, at 4.17 m/s (15 km/h), indicated the profound chilling effects of wind on fingers in cold environments. Finally, the effects of variable blood flow in the finger, known as "cold-induced vasodilatation," were also investigated. Blood flow variations were assumed to be represented by periodic, symmetric triangular waves allowing for gradual opening-closing cycles of blood supply to the tip of the finger. Results of this part of the simulation were compared with measured records of bare finger temperatures. Good conformity was obtained for a plausible pattern of change in blood flow, which was assumed to be provided in its entirety to the tip of the finger alone.

  19. Human thermoregulatory function during exercise and immersion after 35 days of horizontal bed-rest and recovery.

    PubMed

    Mekjavic, Igor B; Golja, Petra; Tipton, Michael J; Eiken, Ola

    2005-10-01

    The present study evaluated the effect of 35 days of experimental horizontal bed-rest on exercise and immersion thermoregulatory function. Fifteen healthy male volunteers were assigned to either a Control (n = 5) or Bed-rest (n = 10) group. Thermoregulatory function was evaluated during a 30-min bout of submaximal exercise on a cycle ergometer, followed immediately by a 100-min immersion in 28 degrees C water. For the Bed-rest group, exercise and immersion thermoregulatory responses observed post-bed-rest were compared with those after a 5 week supervised active recovery period. In both trials, the absolute work load during the exercise portion of the test was identical. During the exercise and immersion, we recorded skin temperature, rectal temperature, the difference in temperature between the forearm and third digit of the right hand (DeltaT(forearm-fingertip))--an index of skin blood flow, sweating rate from the forehead, oxygen uptake and heart rate at minute intervals. Subjects provided ratings of temperature perception and thermal comfort at 5-min intervals. Exercise thermoregulatory responses after bed-rest and recovery were similar. Subjective ratings of temperature perception and thermal comfort during immersion indicated that subjects perceived similar combinations of Tsk and Tre to be warmer and thermally less uncomfortable after bed-rest. The average (SD) exercise-induced increase in Tre relative to resting values was not significantly different between the Post-bed-rest (0.4 (0.2) degrees C) and Recovery (0.5 (0.2) degrees C) trials. During the post-exercise immersion, the decrease in Tre, relative to resting values, was significantly (P < 0.05) greater in the Post-bed-rest trial (0.9 (0.5) degrees C) than after recovery (0.4 (0.3) degrees C). DeltaT(forearm-fingertip) was 5.2 (0.9) degrees C and 5.8 (1.0) degrees C at the end of the post-bed-rest and recovery immersions, respectively. The gain of the shivering response (increase in VO(2) relative to

  20. Double-V block fingers with cruciform recess

    NASA Technical Reports Server (NTRS)

    Voellmer, George M.

    1993-01-01

    In a robot having a gripper including a pair of fingers and a drive motor for driving the fingers toward and away from one another while the fingers remain parallel to each other, the fingers consist of finger pads, which interface with a handle on an object to be grasped, and a shank, which attaches the fingers to the robot gripper. The double-V finger has two orthogonal V-grooves forming in the center of the finger pads and recessed cruciform. The double-V finger is used with a handle on the object to be grasped which is the negative of the finger pads. The handle face consists of V-shaped pads capped with a rectangular cruciform. As the gripper is brought into place near the handle, the finger pads are lined up facing the handle pads. When the finger pad and the handle pad are in proper alignment, the rectangular ridges on the handle fall inside the rectangular grooves on the finger, and the grip is complete.

  1. Transfer of noroviruses between fingers and fomites and food products.

    PubMed

    Tuladhar, Era; Hazeleger, Wilma C; Koopmans, Marion; Zwietering, Marcel H; Duizer, Erwin; Beumer, Rijkelt R

    2013-11-01

    Human norovirus (NoV) contaminated hands are important routes for transmission. Quantitative data on transfer during contact with surfaces and food are scarce but necessary for a quantitative risk assessment. Therefore, transfer of MNV1 and human NoVs GI.4 and GII.4 was studied by artificially contaminating human finger pads, followed by pressing on stainless steel and Trespa® surfaces and also on whole tomatoes and cucumber slices. In addition, clean finger pads were pressed on artificially contaminated stainless steel and Trespa® surfaces. The transfers were performed at a pressure of 0.8-1.9 kg/cm(2) for approximately 2s up to 7 sequential transfers either to carriers or to food products. MNV1 infectivity transfer from finger pads to stainless steel ranged from 13 ± 16% on the first to 0.003 ± 0.009% on the sixth transfer on immediate transfer. After 10 min of drying, transfer was reduced to 0.1 ± 0.2% on the first transfer to 0.013 ± 0.023% on the fifth transfer. MNV1 infectivity transfer from stainless steel and Trespa® to finger pads after 40 min of drying was 2.0 ± 2.0% and 4.0 ± 5.0% respectively. MNV1 infectivity was transferred 7 ± 8% to cucumber slices and 0.3 ± 0.5% to tomatoes after 10 min of drying, where the higher transfer to cucumber was probably due to the higher moisture content of the cucumber slices. Similar results were found for NoVs GI.4 and GII.4 transfers measured in PCR units. The results indicate that transfer of the virus is possible even after the virus is dried on the surface of hands or carriers. Furthermore, the role of fingers in transmission of NoVs was quantified and these data can be useful in risk assessment models and to establish target levels for efficacy of transmission intervention methods. © 2013 Elsevier B.V. All rights reserved.

  2. From viscous fingers to wormholes - interactions between structures emerging in unstable growth

    NASA Astrophysics Data System (ADS)

    Budek, Agnieszka; Kwiatkowski, Kamil; Szymczak, Piotr

    2017-04-01

    Dissolution of porous and fractured rock can lead to instabilities, where long finger-like channels or „wormholes" are spontaneously formed, focusing the majority of the flow. Formation of those structures leads to a significant increase in permeability of the system, and is thus important in many engineering applications, e.g. in acidization during oil and gas recovery stimulation. In this communication, we analyse this process using two different numerical models (a network model and a Darcy scale one). We show that wormhole patterns depend strongly on the amount of soluble material in the system, as quantified by the permeability contrast κ between the dissolved and undissolved medium. For small and intermediate values of κ, a large number of relatively thin and strongly interacting channels are formed. The longer channels attract shorter ones, with loops being formed as a result. However, for large values of κ the pattern gets sparse with individual wormholes repelling each other. Interestingly, a similar succession of patterns can be observed in viscous fingering in a rectangular network of channels. In such a system, anisotropy of the network promotes the growth of long and thin fingers which behave similarly to wormholes. The attraction rate between growing fingers depends strongly on the viscosity ratio, I. The latter plays a role similar to that of permeability ratio for dissolution of porous material. To explain this behaviour, we have created a simple analytical model of interacting fingers, allowing us to quantify their mutual interaction as a function of finger lengths, distances between them and - most importantly - relative permeabilities. The theoretical predictions are in a good agreement with simulation data for both dissolution and viscous fingering processes.

  3. Global analysis of Drosophila Cys2-His2 zinc finger proteins reveals a multitude of novel recognition motifs and binding determinants

    PubMed Central

    Enuameh, Metewo Selase; Asriyan, Yuna; Richards, Adam; Christensen, Ryan G.; Hall, Victoria L.; Kazemian, Majid; Zhu, Cong; Pham, Hannah; Cheng, Qiong; Blatti, Charles; Brasefield, Jessie A.; Basciotta, Matthew D.; Ou, Jianhong; McNulty, Joseph C.; Zhu, Lihua J.; Celniker, Susan E.; Sinha, Saurabh; Stormo, Gary D.; Brodsky, Michael H.; Wolfe, Scot A.

    2013-01-01

    Cys2-His2 zinc finger proteins (ZFPs) are the largest group of transcription factors in higher metazoans. A complete characterization of these ZFPs and their associated target sequences is pivotal to fully annotate transcriptional regulatory networks in metazoan genomes. As a first step in this process, we have characterized the DNA-binding specificities of 129 zinc finger sets from Drosophila using a bacterial one-hybrid system. This data set contains the DNA-binding specificities for at least one encoded ZFP from 70 unique genes and 23 alternate splice isoforms representing the largest set of characterized ZFPs from any organism described to date. These recognition motifs can be used to predict genomic binding sites for these factors within the fruit fly genome. Subsets of fingers from these ZFPs were characterized to define their orientation and register on their recognition sequences, thereby allowing us to define the recognition diversity within this finger set. We find that the characterized fingers can specify 47 of the 64 possible DNA triplets. To confirm the utility of our finger recognition models, we employed subsets of Drosophila fingers in combination with an existing archive of artificial zinc finger modules to create ZFPs with novel DNA-binding specificity. These hybrids of natural and artificial fingers can be used to create functional zinc finger nucleases for editing vertebrate genomes. PMID:23471540

  4. A Study on Self-Heating and Mutual Thermal Coupling in SiGe Multi-Finger HBTs

    NASA Astrophysics Data System (ADS)

    Dwivedi, A. D. D.; D'Esposito, Rosario; Sahoo, Amit Kumar; Fregonese, Sebastien; Zimmer, Thomas

    2016-11-01

    In this paper, the self-heating and mutual thermal coupling in a state-of-the-art SiGe:C multi-finger heterojunction bipolar transistor (HBT) was investigated in static dc operation conditions. Multi-finger HBT structure was created using Sentaurus structure editor with dimensions similar to the layout of SiGe:C multi-finger HBTs in ST-Microelectronics BiCMOS55 (B55) technology ( f T > 300 GHz, f max > 400 GHz) as per ST's BiCMOS55 process design kit guidelines. Three-dimensional thermal technology computer aided design (TCAD) simulations were carried out to obtain the temperature distribution in static dc operation. The lattice temperature ( T Lattice) and heat flux ( F Heat) distribution inside the device were studied. The impact of back-end-of-line (BEOL) layers on static thermal behavior of the state-of-the-art SiGe:C multi finger HBTs was also investigated. The temperature dependent thermal resistance of different fingers of the trench isolated SiGe multi-finger HBT was extracted without and with back-end-of-line (BEOL) effect. An electro-thermal dc compact model of self-heating and mutual thermal coupling in multi-finger HBTs was proposed and applied to compare the modeling results with the TCAD simulation results. Very good agreement was achieved between results obtained from TCAD simulation and those obtained from compact model-based simulation.

  5. Compact Tactile Sensors for Robot Fingers

    NASA Technical Reports Server (NTRS)

    Martin, Toby B.; Lussy, David; Gaudiano, Frank; Hulse, Aaron; Diftler, Myron A.; Rodriguez, Dagoberto; Bielski, Paul; Butzer, Melisa

    2004-01-01

    Compact transducer arrays that measure spatial distributions of force or pressure have been demonstrated as prototypes of tactile sensors to be mounted on fingers and palms of dexterous robot hands. The pressure- or force-distribution feedback provided by these sensors is essential for the further development and implementation of robot-control capabilities for humanlike grasping and manipulation.

  6. PN 2017-24: Finger Lakes LPG

    EPA Pesticide Factsheets

    Finger Lakes LPG Storage, LLC; Two Brush Creek Blvd, Suite 200; Kansas City; Missouri 64112 (Applicant) has applied to the U.S. Environmental Protection Agency (EPA) under the provisions of the Safe Drinking Water Act, 42 U.S.C. 300f et. seq (the Act), for

  7. Viscous fingering of HCI through gastric mucin

    NASA Astrophysics Data System (ADS)

    Bhaskar, K. Ramakrishnan; Garik, Peter; Turner, Bradley S.; Bradley, James Douglas; Bansil, Rama; Stanley, H. Eugene; Lamont, J. Thomas

    1992-12-01

    THE HCI in the mammalian stomach is concentrated enough to digest the stomach itself, yet the gastric epithelium remains undamaged. One protective factor is gastric mucus, which forms a protective layer over the surface epithelium1-4 and acts as a diffusion barrier5,6 Bicarbonate ions secreted by the gastric epithelium7 are trapped in the mucus gel, establishing a gradient from pH 1-2 at the lumen to pH 6-7 at the cell surface8-10. How does HCI, secreted at the base of gastric glands by parietal cells, traverse the mucus layer without acidifying it? Here we demonstrate that injection of HCI through solutions of pig gastric mucin produces viscous fingering patterns11-18 dependent on pH, mucin concentration and acid flow rate. Above pH 4, discrete fingers are observed, whereas below pH 4, HCI neither penetrates the mucin solution nor forms fingers. Our in vitro results suggest that HCI secreted by the gastric gland can penetrate the mucus gel layer (pH 5-7) through narrow fingers, whereas HC1 in the lumen (pH 2) is prevented from diffusing back to the epithelium by the high viscosity of gastric mucus gel on the luminal side.

  8. Fingering and fracturing in granular media

    NASA Astrophysics Data System (ADS)

    Juanes, R.; Holtzman, R.; Szulczewski, M.

    2012-12-01

    Here, we describe the phenomenon of capillary fracturing in granular media. We study the displacement of immiscible fluids in deformable, non-cohesive granular media. Experimentally, we inject air into a thin bed of water-saturated glass beads and observe the invasion morphology. The control parameters are the injection rate, the bead size, and the confining stress. We identify three invasion regimes: capillary fingering, viscous fingering, and "capillary fracturing", where capillary forces overcome frictional resistance and induce the opening of conduits. We derive two dimensionless numbers that govern the transition among the different regimes: a modified capillary number and a fracturing number. The experiments and analysis predict the emergence of fracturing in fine-grained media under low confining stress, a phenomenon that likely plays a fundamental role in many natural processes such as primary oil migration, methane venting from lake sediments, and the formation of desiccation cracks.Examples of experimentally observed patterns. We classify these patterns into three regimes: viscous fingering, capilla